Detection of geomagnetically-induced currents with power line-mounted devices

ABSTRACT

A device for use in a power transmission system to sense GICs. The device may be a part of a reactance-injecting device on a power line, it may be a standalone device, or it may be a part of another type of device. The device may include a sensor to sense magnetic fields (e.g., a Hall effect sensor). The sensor may be positioned in the air gap of a magnetic core formed concentrically around the power line. The signal from the sensor may be converted to a digital signal and separately processed to determine the magnitude of the AC current and the magnitude of the DC (or quasi-DC) current. If the output signal of another A/C current sensor is available, that output signal may be used to adjust/calibrate the determined magnitude of the DC current. The sensor may communicate with other devices in a network to provide GIC information.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a Continuation patent application whichclaims priority to non-provisional U.S. Patent Application No.14/597,377 entitled “DETECTION OF GEOMAGNETICALLY-INDUCED CURRENTS WITHPOWER LINE-MOUNTED DEVICES,” filed on Jan. 15, 2015, which claimspriority to U.S. Provisional Patent Application No. 61/937,220 that isentitled “DETECTION OF GEOMAGNETICALLY-INDUCED CURRENTS WITH POWERLINE-MOUNTED DEVICES,” that was filed on Feb. 7, 2014, the contents ofeach of which are incorporated herein by reference in their entireties.

FIELD

The present invention generally relates to geomagnetically-inducedcurrents on power lines of a power transmission system.

BACKGROUND

Power transmission systems are formed of a complex interconnected systemof generating plants, substations, and transmission and distributionlines. A significant issue currently plaguing power transmission systemsmay be characterized as geomagnetically-induced currents (GICs), whichare currents induced in a power line due to time-varying magnetic fieldsexternal to the Earth and resulting time-varying magnetic fields alongthe Earth's surface. The time-varying magnetic fields external to theEarth often result from solar activity and the activity of otherextra-terrestrial objects.

These GICs have been measured as high as 100 amps for a 20 minuteduration. They are typically in a much lower frequency range than the50-60 Hz AC power that is conducted on power lines in modern powertransmission systems. These GICs typically have such low frequency as tobe quasi-DC currents. Unfortunately, modern transmission systems do nothandle DC currents well. For example, high DC currents may causeundesirable resistive heating of components such as transformer windingswhich can cause such components to fail and result in a partial failureof the power transmission system. Prior art systems for measuring GICscan be bulky, expensive, and require major efforts to be installed. Inmany cases, this is because the GIC sensor requires a break in the powerline in order to install same.

It is against this background that the techniques disclosed herein havebeen developed.

SUMMARY

A first aspect of the present invention is embodied by a device thatmonitors for a geomagnetically-induced current (or GIC) on a power line(e.g., the first aspect also encompasses a method or methods formonitoring for/identifying the existence of a GIC on a power line). Thedescribed device is mounted on the power line and will hereafter bereferred to as a GIC monitor. The GIC monitor includes a magnetic core,which in turn incorporates an air gap. The magnetic core extends aboutat least part of a power line when the GIC monitor is installed ormounted on the power line. A magnetic sensor is positioned in the airgap of the magnetic core. This magnetic sensor is configured to sense amagnetic field(s) and produce an output signal that is representative ofthe magnetic field(s) (e.g., representative of the strength of themagnetic field). A signal processing unit is configured to identify ordetermine the existence of a geomagnetically-induced current (or GIC)using the output signal from the magnetic sensor.

A number of feature refinements and additional features are applicableto the first aspect of the present invention. These feature refinementsand additional features may be used individually or in any combination.The following discussion is applicable to the first aspect, up to thestart of the discussion of a second aspect of the present invention.

The GIC monitor may include an upper housing and a lower housing. Theupper housing and lower housing may be at least partially separable fromone another, and in the installed position or configuration may capturea power line between the upper and lower housings. In one embodiment theupper and lower housings are completely separable from one another, andwhen positioned to capture a power line therebetween may be detachablyconnected in any appropriate manner (e.g., using one or more threadedfasteners; such that the upper and lower housings are then maintained ina fixed position relative to one another).

The magnetic core of the GIC monitor may be of any appropriateconfiguration, including where the magnetic core is a multi-piecestructure. One embodiment has the magnetic core including at least twoseparate core portions or sections in relation to proceeding about apower line (e.g., each core portion or section may correspond with adifferent angular segment relative to an axis along which the power lineextends). Another embodiment has the magnetic core including at leastthree separate core portions or sections in relation to proceeding abouta power line (e.g., each core portion or section may correspond with adifferent angular segment relative to an axis along which the power lineextends). In the case of a three-piece core configuration and when theGIC monitor is mounted on a power line: 1) one of the core portions maybe configured to extend at least generally 180° about the power line; 2)another of the core portions may be configured to extend slightly lessthan 90° about the power line; and 3) another of the core portions maybe configured to extend slightly less than 90° about the power line. Theair gap for the magnetic core may be located between the pair ofslightly less than 90° core portions.

The magnetic core may be characterized as including an upper coresection. The upper core section may extend at least generally 180° abouta power line in the installed configuration. A one-piece configurationmay be used for the upper core section. A plurality of core segmentsdisposed in end-to-end relation could collectively define the upper coresection.

The magnetic core may be characterized as including a lower coreassembly, which in one embodiment includes two lower core sections thatare spaced from one another to define the air gap in which the magneticsensor is disposed. A one-piece configuration may be used for each suchlower core section. A plurality of core segments disposed in end-to-endrelation could collectively and separately define each lower coresection. In any case, a first face of a first of the lower core sectionsmay abut a first face of the noted upper core section, while a secondface of this first lower core section may interface with/define aboundary of the air gap. A first face of a second of the lower coresections may abut a second face of the noted upper core section, while asecond face of this second lower core section may interface with/definea boundary of the air gap. The second faces of the first and secondlower core sections may be separated by the air gap and may at leastgenerally project toward one another.

The magnetic sensor used by the GIC monitor may be of any appropriatetype, including a Hall effect sensor. The Hall effect sensor may outputan analog signal. The GIC sensor may utilize an analog-to-digital (ND)converter to convert the analog output signal from the Hall effectsensor to a digital signal. For instance, the analog output signal fromthe Hall effect sensor may be provided to the ND converter (e.g., via atwisted pair of wires).

The output signal from the magnetic sensor may be in the form of adifferential output signal. The output signal from the magnetic sensormay be provided directly to the signal processing unit. However, one ormore devices may be disposed between the magnetic sensor and the signalprocessing unit, for instance to condition the output signal in anyappropriate manner (e.g., to improve upon the signal-to-noise ratio).One or more of such devices could also be incorporated by the signalprocessing unit.

The signal processing unit may be of any appropriate configuration thatis able to determine a GIC using an output signal from the magneticsensor. The signal processing unit may include a DC processing portionor section to identify the existence of a GIC on the power line usingthe output signal from the magnetic sensor. Such a DC processing portionmay utilize at least one low pass filter of any appropriate type (e.g.,to filter out higher frequency signals, such as signals that arerepresentative of the AC current on the power line). The DC processingportion may further utilize a unit for determining the mean of thesignal(s) that is representative of the DC or quasi-DC current on thepower line. Any such DC or quasi-DC current may be equated with a GIC bythe GIC monitor.

The signal processing unit of the GIC monitor may be configured tocalibrate the value of the GIC that was determined by its DC processingportion. An AC processing portion or section may be utilized by thesignal processing unit for this calibration. Generally, the ACprocessing portion obtains signals that are representative of the ACcurrent on the power line from two separate sources, and uses a ratio ofthese signals to calibrate the value of the GIC that was determined bythe DC processing portion.

The AC processing portion of the signal processing unit may utilize atleast one high pass filter of any appropriate type (e.g., to reduce orfilter out lower frequency signals, such as signals that arerepresentative of a DC or quasi-DC current on the power line). The ACprocessing portion may further utilize a root-mean-square or RMSdetector for determining the magnitude of the signal(s) that isrepresentative of the AC current on the power line. A signal that isrepresentative of the AC current on the power line may be input to thesignal processing unit from another source (e.g., from a current monitorof a reactance module that also may incorporate the GIC monitor). Theratio of these two AC signals may then be used to adjust the GIC thathas been determined by the DC processing portion.

The GIC monitor may include a transmitter and an antenna forcommunicating GIC information to one or more external devices (i.e.,external to the GIC monitor). Any appropriate type of transmitter andantenna may be utilized. Multiple transmitters, multiple antennas, orboth may be used by the GIC monitor. The GIC monitor may be“self-powered” when mounted on the power line (e.g., using power fromthe power line on which the GIC monitor is installed). In one embodimentthe GIC monitor includes a current transformer to provide operatingpower for the GIC monitor.

The GIC monitor may be in the form of a stand-alone unit (i.e.,separately mounted on a power line). Alternatively, the GIC monitor maybe incorporated by another line-mounted device, for instance a reactancemodule. A transformer may be defined when such a reactance module ismounted on a power line (e.g., a single turn transformer). The primaryor the secondary of this transformer may be the power line itself. Theother of the primary or the secondary for this transformer may be one ormore windings of a core for the reactance module (e.g., a first windingwrapped around a first core section of the reactance module, a secondwinding wrapped around a second core section of the reactance module, orboth for the case when the first winding and second winding areelectrically connected). Such a reactance module may be configured toselectively inject reactance into the corresponding power line (thepower line on which the reactance module is mounted). Such a reactancemodule could be configured to selectively inject inductance into thecorresponding power line (e.g., to reduce the current or power flowthrough the power line, or a current-decreasing modal configuration forthe reactance module). Such a reactance module could be configured toinject capacitance into the corresponding power line (e.g., to increasethe current or power flow through the power line, or acurrent-increasing modal configuration for the reactance module).

A reactance module may include any appropriate switch architecture forswitching between two different modes of operation. A reactance modulemay include one or more processors disposed in any appropriateprocessing architecture to control operation of any such switcharchitecture. In a first mode, a reactance module may be configured toinject little or no reactance into the corresponding power line (e.g., abypass or monitoring mode). In a second mode, a reactance module may beconfigured to inject substantially more reactance into the correspondingpower line compared to the first mode (e.g., an injection mode).

A second aspect of the present invention is embodied by a method ofoperating a power transmission system (e.g., the second aspect alsoencompasses a power transmission system that is configured to executethe method(s) described herein). A current on a power line of the powertransmission system is monitored by a geomagnetically-induced currentdevice or monitor (GIC monitor) that is installed on the power line. Anexistence of a geomagnetically-induced current or GIC on the power lineis identified by the GIC monitor (from the monitored current on thepower line). The GIC monitor sends a communication to another componentof the power transmission system in response to an identification of aGIC by the GIC monitor.

A number of feature refinements and additional features are applicableto the second aspect of the present invention. These feature refinementsand additional features may be used individually or in any combination.The GIC monitor used by the second aspect may be in accordance with theabove-described first aspect. A GIC communication in accordance with thesecond aspect could embody information such as the magnitude of theidentified GIC, a time at which the GIC was identified (e.g., a timestamp), the power line on which the GIC was identified, at least thegeneral location of the GIC, and the like. The GIC monitor may send aGIC communication to any appropriate component of the power transmissionsystem, such as a utility-side control system (e.g., an energymanagement system; a supervisory control and data acquisition system; amarket management system).

Any feature of any other various aspects of the present invention thatis intended to be limited to a “singular” context or the like will beclearly set forth herein by terms such as “only,” “single,” “limitedto,” or the like. Merely introducing a feature in accordance withcommonly accepted antecedent basis practice does not limit thecorresponding feature to the singular (e.g., indicating that the GICmonitor includes “an antenna” alone does not mean that the GIC monitorincludes only a single antenna). Moreover, any failure to use phrasessuch as “at least one” also does not limit the corresponding feature tothe singular (e.g., indicating that the GIC monitor includes “anantenna” alone does not mean that the GIC monitor includes only a singleantenna). Use of the phrase “at least generally” or the like in relationto a particular feature encompasses the corresponding characteristic andinsubstantial variations thereof (e.g., indicating that a structure isat least generally cylindrical encompasses this structure beingcylindrical). Finally, a reference of a feature in conjunction with thephrase “in one embodiment” does not limit the use of the feature to asingle embodiment.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic of one embodiment of a power transmission systemhaving line-mounted reactance modules.

FIG. 2A is a perspective view of one end of an embodiment of aline-mountable reactance module.

FIG. 2B is a perspective view of an opposite end of the reactance moduleof FIG. 2A.

FIG. 3 is an exploded, perspective view of the reactance module of FIGS.2A/2B.

FIG. 4A is a perspective view of a lower core assembly positioned withina lower housing section from the reactance module of FIGS. 2A/2B.

FIG. 4B is an exploded, perspective view of the lower core assembly andlower housing section from the reactance module of FIGS. 2A/2B.

FIG. 4C is a cutaway view showing the lower core assembly seated withinthe lower housing section, and taken perpendicularly to the lengthdimension of the reactance module of FIGS. 2A/2B.

FIG. 4D is an enlarged, perspective view of the lower housing sectionfrom the reactance module of FIGS. 2A/2B, and illustrating theencapsulating sections for the lower core assembly.

FIG. 4E is a perspective view of the interior of one of the lower endcaps that is attached to the lower housing section, illustrating anantenna housing disposed therein.

FIG. 4F is an enlarged, perspective view of an insert for an antennadisposed at one of the ends of the reactance module of FIGS. 2A/2B.

FIG. 4G is an enlarged, perspective view of an internal cavity for anantenna disposed at one of the ends of the reactance module of FIGS.2A/2B, illustrating an exciter or probe of the antenna.

FIG. 4H is a perspective view of a variation of the lower housingsection from the reactance module of FIGS. 2A/2B, and which incorporatesinstallation hooks.

FIG. 5A is an exploded, perspective view of an upper core assembly andupper housing section from the reactance module of FIGS. 2A/2B.

FIG. 5B is a bottom view of the upper core assembly seated within theupper housing section from the reactance module of FIGS. 2A/2B.

FIG. 5C is a cutaway view showing the upper core assembly seated withinthe upper housing section, and taken perpendicularly to the lengthdimension of the reactance module of FIGS. 2A/2B.

FIG. 5D is a perspective view of the interior of the upper housingsection from the reactance module of FIGS. 2A/2B, and illustrating theencapsulating sections for the upper core assembly.

FIG. 6A is a perspective view of the lower core assembly from thereactance module of FIGS. 2A/2B.

FIG. 6B is a perspective view of the lower core section for the lowercore assembly from the reactance module of FIGS. 2A/2B, illustratingspacers installed on faces of the individual lower core segments thatcollectively define the lower core section.

FIG. 6C is a perspective view of the lower core section for the lowercore assembly from the reactance module of FIGS. 2A/2B, illustrating thefaces of the lower core segments that collectively define the lower coresection (before installing the noted spacers).

FIG. 7A is a perspective view of the upper core assembly from thereactance module of FIGS. 2A/2B.

FIG. 7B is a top perspective view of the upper core section for theupper core assembly from the reactance module of FIGS. 2A/2B.

FIG. 7C is a bottom perspective view of the upper core section for theupper core assembly from the reactance module of FIGS. 2A/2B,illustrating spacers installed on faces of the individual lower coresegments that collectively define the lower core section.

FIG. 7D is a bottom perspective view of the upper core section for theupper core assembly from the reactance module of FIGS. 2A/2B,illustrating the faces of the individual upper core segments thatcollectively define the upper core section (before installing the notedspacers).

FIG. 8A is one perspective view of the lower core assembly andelectronics from the reactance module of FIGS. 2A/2B.

FIG. 8B is another perspective view of the lower core assembly andelectronics from the reactance module of FIGS. 2A/2B.

FIG. 9 is one embodiment of a protocol for assembling the reactancemodule of FIGS. 2A/2B.

FIG. 10 is an electrical block diagram for an embodiment of thereactance module of FIGS. 2A/2B.

FIG. 11A is a schematic of an embodiment of a power supply from theelectrical block diagram of FIG. 10.

FIG. 11B is a schematic of an embodiment of a power supply and a currentmonitor from the electrical block diagram of FIG. 10.

FIG. 12A is a schematic of an embodiment of a fault protection systemfor the reactance module of FIGS. 2A/2B.

FIG. 12B is an embodiment of a fault current protocol that may be usedby the fault protection system of FIG. 12A to execute a plurality ofbypass sequences.

FIG. 12C is a flow chart illustrating one embodiment of a first bypasssequence that may be executed by the fault protection system of FIG.12A.

FIG. 12D is a flow chart illustrating one embodiment of a second bypasssequence that may be executed by the fault protection system of FIG.12A.

FIG. 12E is a flow chart illustrating one embodiment of a third bypasssequence that may be executed by the fault protection system of FIG.12A.

FIG. 13A is a schematic of an embodiment of a power transmission systemwith distributed control for multiple arrays of reactance modules of thetype presented in FIGS. 2A/2B.

FIG. 13B is a schematic of a reactance module or distributed seriesreactor (DSR) array controller used to provide distributed control forthe power transmission system of FIG. 13A.

FIG. 13C is an electrical block diagram that may be utilized by DSRarray controllers from the power transmission system of FIG. 13A.

FIG. 13D is a diagram of a system condition/contingency data structurethat may be incorporated by DSR array controllers from the powertransmission system of FIG. 13A.

FIG. 13E is an embodiment of an operations protocol that may be used bythe power transmission system of FIG. 13A to control operation ofindividual reactance modules.

FIG. 13F is an embodiment of a system condition/contingency-basedprotocol that may be used by the power transmission system of FIG. 13Ato control operation of individual reactance modules.

FIG. 13G is another embodiment of a system condition/contingency-basedprotocol that may be used by the power transmission system of FIG. 13Ato control operation of individual reactance modules.

FIG. 14 is a block diagram of one embodiment of a GIC monitoring system.

FIGS. 15A and 15B are an exploded view and a non-exploded view ofcomponents of a magnetic core for the GIC monitoring system of FIG. 14.

FIG. 16 is a block diagram of an embodiment of a signal processing unitfor the GIC monitoring system of FIG. 14.

FIG. 17 is an exploded view illustrating how the GIC monitoring systemof FIG. 14 could be incorporated into the DSR of FIG. 2A.

FIG. 18 is an exploded view illustrating how the GIC monitoring systemof FIG. 14 could be implemented in a standalone device.

FIG. 19 is a schematic of a power transmission system that includes aplurality of GIC sensors.

FIG. 20 is one embodiment of a GIC monitoring protocol that may be usedby the power transmission system of FIG. 19.

DETAILED DESCRIPTION

While the disclosure is susceptible to various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and are herein described in detail. It shouldbe understood, however, that it is not intended to limit the disclosureto the particular form disclosed, but rather, the disclosure is to coverall modifications, equivalents, and alternatives falling within thescope as defined by the claims.

One embodiment of a power transmission system is illustrated in FIG. 1as identified by reference numeral 10. The power transmission system 10includes a plurality of power lines 16 (three in the illustratedembodiment, for providing three-phase power) that extend between anelectric power source 12 and a load 22.

Any appropriate number of electrical power sources 12 and loads 22 maybe associated with the power transmission system 10. A plurality oftowers 14 of any appropriate size, shape, and/or configuration maysupport the various power lines 16 at appropriately spaced locations.The power lines 16 may be of any appropriate type, for instance powertransmission lines (larger capacity) or distribution lines (lowercapacity).

A plurality of distributed series reactors (DSRs) or “reactance modules”are installed on each of the power lines 16 of the power transmissionsystem 10, and are identified by reference numeral 24. Althoughhereafter these devices may be referred to as “DSRs”, it should beappreciated such a reference is actually to a “reactance module.” Anyappropriate number of DSRs 24 may be installed on a given power line 16and using any appropriate spacing. Each DSR 24 may be installed on apower line 16 at any appropriate location, including in proximity to aninsulator. Generally, each DSR 24 (more generally each reactance module)may be configured/operated to inject reactance (e.g., inductance,capacitance) into the corresponding power line 16. That is, a given DSR24 (more generally a given reactance module) may be of a configurationso as to be able to inject inductance into the power line 16 on which itis mounted (e.g., the injected reactance may be an inductive reactanceor inductance, which may reduce the flow of current through the powerline 16 on which the DSR 24 is mounted). A given DSR 24 (more generallya given reactance module) may also be of a configuration so as to beable to inject capacitance into the power line 16 on which it is mounted(e.g., the injected reactance may be a capacitive reactance orcapacitance, which may increase the flow of current through the powerline 16 on which the DSR 24 is mounted).

FIGS. 2A, 2B, and 3 illustrate a representative configuration for theDSRs 24 presented in FIG. 1, and which is identified by referencenumeral 30. Generally, the configuration of the DSR or reactance module30 presented herein is of the type that provides for the injection ofinductance into a power line 16 on which it is mounted. However and asin the case of the DSR 24 discussed above, the DSR 30 could beconfigured so as to inject capacitance into the power line 16 on whichit is mounted (not shown).

The DSR 30 of FIGS. 2A, 2B, and 3 is configured for installation on apower line 16 without requiring a break in the same. In this regard, ahousing 40 of the DSR 30 includes a first or lower housing section 80and a second or upper housing section 120 that are detachably connectedin any appropriate fashion. A first or lower end cap 90 and a second orupper end cap 124 of the housing 40 are positioned on one end 42 (e.g.,a power end) of the DSR 30, and another lower end cap 90 and upper endcap 124 are positioned at the opposite end 44 (e.g., a control end) ofthe housing 40. As will be discussed in more detail below, the DSR 30uses a pair of cavity-backed slot antennas 100 (e.g., FIGS. 4E, 4F, and4G), one being positioned at least generally at each end 42, 44 of theDSR 30. As such, a slot 94 for the antenna 100 extends through the wallthickness of the housing 40 at each of its ends 42, 44.

The housing 40 of the DSR 30 at least substantially encloses a coreassembly 50 (e.g., in the form of a single turn transformer). Althoughthe core assembly 50 (e.g., collectively defined by core assemblies 130,160) is illustrated as having a round or circular outer perimeter, othershapes may be appropriate. A first or lower core assembly 130 isdisposed within the lower housing section 80 (e.g., within a compartment86), while a second or upper core assembly 160 is disposed within theupper housing section 120. The lower core assembly 130 includes a firstor lower winding 144, while the upper core assembly 160 includes asecond or upper winding 174. The windings 144, 174 may be electricallyinterconnected in any appropriate manner. The lower core assembly 130and the upper core assembly 160 are collectively disposed about thepower line 16 on which the DSR 30 is installed. When the core assembly50 is installed on a power line 16, it collectively defines a singleturn transformer, where the primary of this single turn transformer isthe power line 16, and where the secondary of this single turntransformer is defined by the windings 144, 174 for the illustratedembodiment. However, the secondary of this single turn transformer couldbe comprised of only the lower winding 144 or only the upper winding174. For example, the lower core assembly 130 may include the lowerwinding 144, and the upper core assembly 160 may not include the upperwinding 174. Similarly, the lower core assembly 130 may not include thelower winding 144, and the upper core assembly 160 may include the upperwinding 174. As such, the primary of the noted single turn transformeris the power line 16, and the secondary of this single turn transformermay be the lower winding 144 by itself, may be the upper winding 174 byitself, or collectively may be the lower winding 144 and the upperwinding 174. Furthermore, while the power line 16 is described herein asthe primary winding and some combination of the lower and upper windings144, 174 are described herein as the secondary winding, as that may beconventional when describing the power line 16 when it is part of asingle-turn transformer, for the purposes of the device 202 to bedescribed herein, one could refer to the combination of the lower andupper windings 144, 174 as the primary winding and the power line 16 asthe secondary winding. In each case, the function is the same.

The housing 40 of the DSR 30 also at least substantially encloseselectronics 200 for undertaking various operations of the DSR 30. Theelectronics 200 are disposed within the lower housing section 80, andare separated from the lower core assembly 130 by a partition or barrier82. This partition 82 may provide shielding for the electronics 200,such as shielding against electromagnetic interference. Any appropriateshielding material may be utilized for the partition 82.

A pair of first or lower clamps 64 are associated with the lower coreassembly 130, and may be anchored relative to the lower housing section80 in any appropriate manner. A pair of second or upper clamps 66 areassociated with the upper core assembly 160, and may be anchoredrelative to the upper housing section 120 in any appropriate manner.Although the clamps 64, 66 could directly engage the power line 16, inthe illustrated embodiment a pair of line guards 20 are mounted on thepower line 16 at locations that correspond with the position of eachpair of clamps 64/66.

Additional views of the lower housing section 80 and lower core assembly130 are presented in FIGS. 4A-4G. FIG. 4A shows the lower core assembly130 being positioned within the lower housing section 80, while FIG. 4Bshows the lower core assembly 130 being exploded away from the lowerhousing section 80. A barrier or partition 82 is associated with thelower housing section 80, and defines a lower or electronics compartment84 and an upper or core compartment 86 (e.g., FIG. 4C). In oneembodiment, the electronics compartment 84 is at least substantiallywaterproof. Moreover and as noted, the electronics compartment 84 may beshielded from the core assembly 50, for instance by the above-notedbarrier or partition 82. In any case, the electronics 200 are disposedwithin the electronics compartment 84, while the lower core assembly 130is disposed within the core compartment 86.

The lower core assembly 130 is retained by encapsulating sections 150,152 within the lower housing section 80 (e.g., FIGS. 4B, 4C, and 4D). Inone embodiment, the encapsulating sections 150, 152 are each in the formof a silicone elastomer encapsulant such as Sylgard® available from DowCorning (the Sylgard® for the encapsulating sections 150, 152 may bematched to the dielectric and operational performance rating of the DSR30). The encapsulating section 152 is disposed between the lower coreassembly 130 and the partition 82 of the lower housing section 80. Theencapsulating section 150 is disposed between the lower core assembly130 and the power line 16. A first or lower power line cavity 138extends along the length of the lower core assembly 130 (within theencapsulating section 150) for receiving a lower portion of thecorresponding power line 16. FIG. 4D shows the relative position of theencapsulating sections 150, 152, with the lower core assembly 130 beingremoved to show this relative position.

A pair of first or lower end caps 90 are disposed at each of the twoends 42, 44 of the DSR 30, and are each detachably connected in anyappropriate manner to the lower housing section 80. Each lower end cap90 includes an end wall 92. A slot 94 extends through the entirethickness of the end wall 92, may be of any appropriate shape, and ispart of the associated antenna 100. The slot 94 may be characterized ashaving a “folded configuration” to provide for a desired length. Anantenna compartment 98 is disposed within each lower end cap 90. An endplate 88 (FIG. 4F) separates this antenna compartment 98 from theelectronics compartment 84. Generally, each antenna 100 utilizes anaperture that extends through the housing 40 of the DSR 30, and thisaperture may be of any appropriate shape/size, and may be incorporatedin any appropriate manner (e.g., such an aperture could actually projectdownwardly when the DSR 30 is installed on a power line 16).

Other components of the antenna 100 are illustrated in FIGS. 4E, 4F, and4G. Again, an antenna 100 is located at least generally at the two ends42, 44 of the DSR 30 in the illustrated embodiment, with each antenna100 being located within its corresponding antenna compartment 98. Eachantenna 100 includes an antenna housing 102 of any appropriatesize/shape and which may be formed from any appropriate material orcombination of materials. The antenna housing 102 includes a backsection 104, along with a plurality of side sections 106 (four in theillustrated embodiment) that extend to the back side of the end wall 92of the corresponding lower end cap 90. As such, the end wall 92 of thecorresponding lower end cap 90 may be characterized as defining an endof the antenna housing 102 that is disposed opposite of the back section104.

An insert 110 (FIG. 4F) may be disposed within the antenna housing 102.This insert 110 may be formed from any appropriate material, forinstance Teflon®. An insert 110 may not be required in all instances. Inany case, a projection 112 may be formed on an end of the insert 110,and extends into the slot 94 on the end wall 92 of its correspondinglower end cap 90. The antenna housing 102 defines an internal cavity 108having an exciter or probe 114. The antenna 100 may be characterized asa slotted antenna or as a cavity-backed slot antenna. Notably, neitherantenna 100 protrudes beyond an outer perimeter of the housing 40 forthe DSR 30.

A variation of the DSR 30 is presented in FIG. 4H in the form of a DSR30′. Corresponding components of these two embodiments are identified bythe same reference numerals. Those corresponding components that differare further identified by a “single prime” designation in FIG. 4H.Unless otherwise noted, the DSR 30′ includes the same features as theDSR 30.

One difference between the DSR 30 and the DSR 30′ is that there is asingle antenna 100 in the case of the DSR 30′ of FIG. 4H. This singleantenna 100 may be disposed at an appropriate location between the ends42, 44 of the DSR 30 (e.g., within the housing 40). In the illustratedembodiment, the antenna 100 is disposed at least generally midwaybetween the ends 42, 44 of the DSR 30′. Relatedly, the end wall 92′ ofthe two lower end caps 90′ need not include a slot 94. Instead, asimilar slot would be included on the bottom of the housing 40 toaccommodate the antenna 100 for the DSR 30′ (i.e., on the surface of thefirst housing section 80 that projects in a downward direction when theDSR 30′ is installed on a power line 16).

Another difference between the DSR 30 and the DSR 30′ of FIG. 4H is thatthe DSR 30′ includes a pair of installation hooks 96. One installationhook 96 may be disposed within the lower end cap 90′ at each of the ends42, 44 of the DSR 30′. Each installation hook 96 may be anchored in anyappropriate manner relative to the first housing section 80 of the DSR30′. That is, the installation hooks 96 will move collectively with thelower housing section 80 during installation of the DSR 30′ on a powerline 16. It should be appreciated that the installation hooks 96 couldalso be integrated into the structure of the DSR 30 in any appropriatemanner.

The installation hooks 96 facilitate installation of the DSR 30′ on apower line 16. Generally, the first housing section 80 of the DSR 30′may be suspended from a power line 16 by disposing each of theinstallation hooks 96 on the power line 16 (the installation hooks 96engaging the power line 16 at locations that are spaced along the lengthof the power line 16; the installation hooks 96 could be positioneddirectly on the power line 16, or on a corresponding line guard 20). Thesecond housing section 120 may then be positioned over each of the powerline 16 and the first housing section 80. At this time, the secondhousing section 120 may be supported by the power line 16 and/or thefirst housing section 80.

With the second housing section 120 being properly aligned with thefirst housing section 80, a plurality of fasteners may be used to securethe second housing section 120 to the first housing section 80. As thesecond housing section 120 is being connected to the first housingsection 80, (e.g., as the various fasteners are rotated), the firsthousing section 80 may be lifted upwardly in the direction of the secondhousing section 120, which in turn will lift the installation hooks 96(again, fixed relative to the first housing section 80) off of the powerline 16. Ultimately, the installation hooks 96 are received within thehollow interior of the second or upper end caps 124 of the secondhousing section 120. Once the second housing section 120 and the firsthousing section 80 are appropriately secured together, both installationhooks 96 will be maintained in spaced relation to the power line 16.

Additional views of the upper housing section 120 and upper coreassembly 160 are presented in FIGS. 5A-5D. FIG. 5A shows the upper coreassembly 160 being exploded away from the upper housing section 120 (theupper core assembly 160 being received within a core compartment 122 ofthe upper housing section 120), while FIG. 5B shows the upper coreassembly 160 being positioned within the upper housing section 120 (morespecifically within the core compartment 122). A pair of second or upperend caps 124 are detachably connected to opposite ends of the upperhousing section 120 and define corresponding portions of the two ends42, 44 of the DSR 30.

Referring now to FIG. 5C, the upper core assembly 160 is retained byencapsulating sections 180, 182 within the upper housing section 120. Inone embodiment, the encapsulating sections 180, 182 are a siliconeelastomer encapsulant such as the above-noted Sylgard®. Theencapsulating section 182 is disposed between the upper core assembly160 and the upper housing section 120. The encapsulating section 180 isdisposed between the upper core assembly 160 and the power line 16. Asecond or upper power line cavity 168 extends along the length of theupper core assembly 160 (within the encapsulating section 180) forreceiving an upper portion of the corresponding power line 16. FIG. 5Dshows the relative position of the encapsulating sections 180, 182, withthe upper core assembly 160 being removed to show this relativeposition.

FIGS. 6A-6C present various enlarged views pertaining to the lower coreassembly 130. The lower core assembly 130 includes a first or lower coresection 132 (FIG. 6B) having a pair of oppositely disposed ends 136. Afirst or lower winding 144 (FIG. 6A) wraps around the lower core section132 between its two ends 136.

The lower core section 132 of the lower core assembly 130 iscollectively defined by a plurality of first or lower core segments 140that are disposed in end-to-end relation. Any appropriate number ofindividual lower core segments 140 may be utilized (four in theillustrated embodiment). Adjacent lower core segments 140 may bedisposed in abutting relation, or adjacent lower core segments 140 maybe separated from one another by an appropriate space (typically a smallspace, such as a space of no more than about ⅛ inches).

Each lower core segment 140 includes a pair of faces 142 (FIGS. 6C and4C) that extend along opposite sides of the corresponding lower coresegment 140 in its length dimension. The faces 142 on each of the twosides of the lower core section 132 may be characterized as collectivelydefining a core section face (i.e., the lower core section 132 may becharacterized as having two core section faces, with each of the coresection faces being defined by the faces 142 of the lower core segments140 on a common side of the lower core section 132). Each face 142 is inthe form of an at least substantially planar or flat surface. The faces142 of the various lower core segments 140 are disposed in at leastsubstantially coplanar relation (e.g., the various faces 142 are atleast substantially disposed within a common reference plane). Aseparate spacer 146 (e.g., FIGS. 6A, 6B, 4C) is appropriately secured(e.g., bonded; adhesively attached) to each face 142 of each lower coresegment 140. A single spacer could collectively extend over those faces142 of the various lower core segments 142 that are on a common side ofthe lower core segments 142 (not shown). In any case and in oneembodiment, each spacer 146 is in the form of tape or a dielectric film,for instance a polyamide film (e.g., Kapton® tape available from DuPontCompany). Kapton® tape dimensions for each spacer 146 (as well asspacers 176 addressed below) may be specific to the magnetization andloss performance ratings of the DSR 30.

The spacers 146 on a common side of the lower core section 132 may becharacterized as collectively defining an interface 134. Therefore, thelower core section 132 includes a pair of laterally spaced interfaces134 that each extend along the entire length of the lower core section132 (e.g., between its opposing ends 136). One embodiment has eachspacer 146 having a thickness within a range of about 0.07 inches toabout 0.13 inches, although other thicknesses may be appropriate (e.g.,to realize a desired amount of reactance to be injected into the powerline 16 by the core assembly 50). Generally, the spacers 146 associatedwith the lower core section 132 contribute to providing and maintaininga desired and controlled physical and electric/magnetic spacing betweenthe lower core assembly 130 and the upper core assembly 160.

FIGS. 7A-7D present various enlarged views pertaining to the upper coreassembly 160. The upper core assembly 160 includes a second or uppercore section 162 (FIG. 7B) having a pair of oppositely disposed ends166. A second or upper winding 174 (FIG. 7A) wraps around the upper coresection 162 between its two ends 166.

The upper core section 162 of the upper core assembly 160 iscollectively defined by a plurality of second or upper core segments 170that are disposed in end-to-end relation. Any appropriate number ofindividual upper core segments 170 may be utilized (four in theillustrated embodiment). Adjacent upper core segments 170 may bedisposed in abutting relation, or adjacent upper core segments 170 maybe separated from one another by an appropriate space (e.g., inaccordance with the discussion presented above on the lower core section132).

Each upper core segment 170 includes a pair of faces 172 (FIGS. 7D and5C) that extend along opposite sides of the corresponding upper coresegment 170 in its length dimension. The faces 172 on each of the twosides of the upper core section 162 may be characterized as collectivelydefining a core section face (i.e., the upper core section 162 may becharacterized as having two core section faces, with each of the coresection faces being defined by the faces 172 of the upper core segments170 on a common side of the upper core section 162). Each face 172 is inthe form of an at least substantially planar or flat surface. The faces172 of the various upper core segments 170 are disposed in at leastsubstantially coplanar relation (e.g., the various faces 172 are atleast substantially disposed within a common reference plane). Aseparate spacer 176 (e.g., FIGS. 7A, 7B, 5C) is appropriately secured(e.g., bonded; adhesively attached) to each face 172 of each upper coresegment 170. A single spacer could collectively extend over those faces172 of the various upper core segments 170 that are on a common side ofthe upper core segments 170. In any case and in one embodiment, eachspacer 176 is in the form of tape or a dielectric film, for instance apolyamide film (e.g., Kapton® tape, noted above).

The spacers 176 on a common side of the upper core section 162 may becharacterized as collectively defining an interface 164. Therefore, theupper core section 162 includes a pair of laterally spaced interfaces164 that each extend along the entire length of the upper core section162 (e.g., between its opposing ends 166). One embodiment has eachspacer 176 having a thickness within a range of about 0.07 inches toabout 0.13 inches, although other thicknesses may be appropriate (e.g.,to realize a desired amount of reactance to be injected into the powerline 16 by the core assembly 50). Generally, the spacers 176 associatedwith the upper core section 162 contribute to providing and maintaininga desired and controlled physical and electric/magnetic spacing betweenthe lower core assembly 130 and the upper core assembly 160.

When the upper core assembly 160 is properly aligned with the lower coreassembly 130, the interface 164 on one side of upper core assembly 160will engage the interface 134 on the corresponding side of the lowercore assembly 130. Similarly, the interface 164 on the opposite side ofupper core assembly 160 will engage the interface 134 on thecorresponding side of the lower core assembly 130. Having each spacer176 on the upper core assembly 160 engage a corresponding spacer 146 onthe lower core assembly 130 maintains a desired physical andelectric/magnetic spacing between the upper core assembly 160 and thelower core assembly 130 (e.g., a spacing within a range of about 0.14inches to about 0.26 inches at the corresponding interfaces 134/164,although other spacings may be appropriate).

FIGS. 8A and 8B present additional views of the lower core assembly 130and the electronics 200. The electronics 200 includes a printed circuit,control board, or controller 214, a second electrical switch 206 (e.g.,a contactor, bypass switch, or contact relay), a first electrical switch204 (e.g., an SCR), an MOV (metal oxide varistor) 230, and a faultprotection system 220 (again, these components are located within theelectronics compartment 84 of the lower housing section 80, and areisolated from the core assembly 50 by the barrier or partition 82). Aseparate antenna cable 62 is also located within the electronicscompartment 84 and extends from the controller 214 to each of the twoantennas 100 for the DSR 30. The first electrical switch 204 (e.g., SCR)and the fault protection system 220 are utilized by the DSR 30 in faultcurrent or surge conditions encountered in the power line 16 on whichthe DSR 30 is mounted. The MOV 230 is used by the DSR 30 for lightningprotection. The controller 214 controls operation of the secondelectrical switch 206 (e.g., contactor), which in turn establishes themode of the core assembly 50. The core assembly 50 may be disposed ineither of first or second modes. In the second or injection mode, thecore assembly 50 injects reactance into the power line 16 on which theDSR 30 is mounted (inductance for the illustrated configuration of theDSR 30, although the DSR 30 may be configured to instead injectcapacitance as noted above). In the first or non-injection mode, thecore assembly 50 injects little or no reactance into the power line 16on which the DSR 30 is mounted.

One embodiment of a protocol for assembling the above-described DSR 30is presented in FIG. 9 and is identified by reference 190. The protocol190 is applicable to assembling the lower core assembly 130 within thelower housing section 80, as well as to assembling the upper coreassembly 160 within the upper housing section 120 (includingsimultaneously (e.g., using different machine sets) or sequentially(e.g., using a common machine set). Hereafter, the protocol 190 will bedescribed with regard to assembling the lower core assembly 130 withinthe lower housing section 80.

The lower core section 132 may be assembled by disposing the first coresegments 140 in alignment (step 191). The ends of adjacent first coresegments 140 may be disposed in abutting relation, or a small space mayexist between each adjacent pair of first core segments 140. In oneembodiment, the various first core segments 140 are positioned within anappropriate jig for purposes of step 191 of the protocol 190.

The first winding 144 may be associated with the assembled first coresection 132 pursuant to step 192 of the protocol 190. The first winding144 may be created/defined “off the first core section 132”, and thenseparately positioned on the first core section 132 (so as to extendbetween its ends 136) for purposes of step 192. Another option would beto wind wire on the assembled first core section 132 (around its ends136) to create/define the first winding 144 for purposes of step 192 ofthe protocol 190. In any case, the first winding 144 may be attached tothe first core section 132 in any appropriate manner, for instance usingan epoxy (step 193). In one embodiment, the first winding 144 isseparately attached to each of the individual first core segments 140that collectively define the first core section 132.

Spacers 146 may be installed on the various faces 142 of the first coresegments 140 that collectively define the first core section 132 (step194). Steps 192-194 may be executed in any appropriate order (e.g., step194 could be executed prior to or after step 192). In one embodiment, aseparate spacer 146 is provided for each face 142 of each first coresegment 140. Any appropriate adhesive and/or bonding technique may beused to attach the spacers 146 to the corresponding first core segment140 (more specifically, to one of its faces 142).

The first core assembly 130 is positioned within the first housingsection 80 (step 195). The lower core assembly 130 is magnetically heldrelative to the lower housing section 80 (step 196). An appropriate jigmay be used for purposes of step 196. Step 196 may entail using one ormore magnets to maintain the various faces 142 (of the lower coresegments 140 that collectively define the lower core section 132) in atleast substantially coplanar relation (e.g., to dispose the faces 142 ina common reference plane), to maintain a desired spacing between thelower core assembly 130 and the interior of the lower housing section 80in a desired spaced relation (e.g., the partition 82), or both. In oneembodiment, each face 142 of each lower core segment 140 is positionedagainst a flat or planar surface of a corresponding magnet (e.g., aseparate magnet may be provided for each lower core segment 140).Thereafter, a potting material (e.g., Sylgard®) is injected toencapsulate all but the upper surfaces of the spacers 146 of the lowercore assembly 130 within the lower housing section 80 (step 197), andthis potting material is allowed to cure in any appropriate manner todefine the encapsulating sections 150, 152 discussed above (step 198).

A representative electrical block diagram of the DSR 30 is presented inFIG. 10. The DSR 30 may be characterized as including a first device 202(e.g., a transformer that includes the core assembly 50 of the DSR 30),the above-noted first electrical switch 204 (e.g., an SCR), theabove-noted second electrical switch 206 (e.g., a contact relay), acurrent transformer 208, a power supply 210, a current monitor 212, andthe above-noted controller 214. Again, the DSR 30 may be mounted on apower line 16 such that reactance may be injected into the power line16. The first device 202 may be in the form of (or part of) a reactanceinjecting circuit, for instance a single turn transformer. The firstdevice 202 may be disposable in each of first and second modes. Forexample, switching the first device 202 from the first mode to thesecond mode may increase the injected reactance being input to the powerline 16 when the DSR 30 is mounted on the power line 16. The firstdevice 202 may be operably connected to the controller 214 via the firstelectrical switch 204 (e.g., SCR) and/or the second electrical switch206 (e.g., a contact relay). In other words, the first device 202 may beoperably connected with the first electrical switch 204, the secondelectrical switch 206, and/or the controller 214.

In one embodiment, the first electrical switch 204 (e.g., an SCR) may bea solid-state semiconductor device, for instance a thyristor pair. Thefirst electrical switch 204 may be operably connected to the firstdevice 202 and/or the controller 214. In this regard, the firstelectrical switch 204 may be operable to control the injection ofreactance into the power line 16. For example and when the firstelectrical switch 204 is closed, a minimum level of reactance,corresponding to the first device 202 leakage reactance, is injectedinto power line 16. In another example and when the first electricalswitch 204 is open and the second electrical switch 206 (e.g., a contactrelay) is open, reactance is injected into power line 16. As will bediscussed in more detail below, the first electrical switch 204 also maybe operable to pass an overcurrent.

The controller 214 may be any computerized device (e.g., amicrocontroller) that is operable to manage the operation of multipledevices and/or communicate with multiple devices in order to implementone or more control objectives. For example, the controller 214 may beoperable to switch the first device 202 from the first mode to thesecond mode and/or communicate with any device of the DSR 30. In thisregard, the controller 214 may be operably connected to the firstelectrical switch 204 (e.g., an SCR), the second electrical switch 206(e.g., a contact relay), the first device 202, the current monitor 212,and/or the power supply 210. The controller 214 may switch the firstdevice 202 from the first mode to the second mode via the secondelectrical switch 206.

The first mode for the DSR 30 may be characterized as a bypass mode andthe second mode for the DSR 30 may be characterized as an injectionmode. When the second electrical switch 206 is closed (i.e., isconducting), the first device 202 is in bypass mode (e.g., the firstdevice 202 is shorted) and little or no reactance is injected into thepower line 16 via the DSR 30. When the second electrical switch 206 isopen (such that the first device 202 is not shorted) the first device202 is in injection mode where reactance is injected into the power line16. At this time and if the DSR 30 incorporates the first electricalswitch 204, the first electrical switch 204 should also be open (alongwith the second electrical switch 206, and again such that the firstdevice 202 is not shorted) such that the first device 202 is ininjection mode where reactance is injected into the power line 16.

The controller 214 may switch the first device 202 from bypass mode toinjection mode when the current monitor 212 determines that a current ofthe power line 16 satisfies a predetermined threshold. For example, thecurrent monitor 212 may be operable to measure the current on the powerline 16 (at the DSR 30) and communicate the measured current to thecontroller 214. If the measured current satisfies the predeterminedthreshold (e.g., if the current is greater than the threshold, or isequal to or greater than the threshold, as the case may be), thecontroller 214 may switch the first device 202 from bypass mode toinjection mode by opening the second electrical switch 206 (e.g.,contact relay) such that reactance is injected into the power line 16.Similarly, if the measured current thereafter no longer satisfies thepredetermined threshold (e.g., if the measured current drops below thepredetermined threshold), the controller 214 may switch the first device202 from injection mode back to bypass mode by closing the secondelectrical switch 206 such that the first device 202 is shorted and suchthat no substantial reactance is injected into the power line 16. Assuch, the controller 214 may be operable to switch the first device 202between the bypass and injection modes.

The current monitor 212 may measure the current on the power line 16 viathe current transformer 208. In this regard, the current transformer 208may be mounted on the power line 16 and may be a separate component fromthe first device 202. In one embodiment, the current transformer 208 maybe operable to produce a reduced current that is proportional to thecurrent of the power line 16 such that the current may be processedand/or measured by a measuring device (e.g., the current monitor 212)and/or the current may provide power to electronic components (e.g., thepower supply 210). The power supply 210 may be operably connected withthe current transformer 208 and/or the controller 214. In this regard,the power supply 210 may receive power from the current transformer 208and provide power to the controller 214.

The DSR 30 may be mounted on the power line 16 such that an injectedreactance may be input to the power line 16. In one embodiment, theinjected reactance may be an inductive reactance (e.g., inductance). Forexample, when inductance is injected into the power line 16, the flow ofcurrent in the power line 16 may be reduced and diverted tounderutilized power lines in interconnected and/or meshed powernetworks. In another embodiment, the injected reactance may be acapacitive reactance (e.g., capacitance). For example, when capacitanceis injected into the power line 16, the flow of current in the powerline 16 may be increased and diverted from power lines in interconnectedand/or meshed power networks.

FIG. 11A illustrates one embodiment that may be used as the power supply210 for the DSR 30 addressed above in relation to FIG. 10. The powersupply 210 of FIG. 11A includes a bridgeless power factor correctioncircuit or a bridgeless PFC 310 and a regulator 322. As discussed above,the power supply 210 may receive power from the current transformer 208(where the power line 16 is the primary of the current transformer 208),and the current transformer 208 may be operable to produce a reducedcurrent that is proportional to the current on the power line 16 suchthat the current transformer 208 may provide power to the power supply210. In one embodiment, the current of the power line 16 may becharacterized as a first current and the reduced current provided by thecurrent transformer 208 may be characterized as a second current. Inthis regard, the current transformer 208 receives the first current andoutputs the second current, the second current is different than thefirst current, and the second current is proportional to the firstcurrent.

The second current may be based at least on the number of turns of asecondary winding (not illustrated) of the current transformer 208. Forexample, the secondary winding of the current transformer 208 maycomprise 100 turns. In this example, the second current would be 1/100of the first current (i.e., the first current is 100 times the secondcurrent). The current transformer 208 may be configured to provide anydesired reduction of the current on the power line 16.

The bridgeless PFC 310 includes the current transformer 208, a firstcontrollable switch 312, a second controllable switch 314, a firstrectifier 316, a second rectifier 318, and a capacitor 320. The firstrectifier 316 may be operably connected to the first controllable switch312 and the second rectifier 318 may be operably connected to the secondcontrollable switch 314. In this regard, the operation of the first andsecond rectifiers 316, 318 may be dependent on the operation of thefirst and second controllable switches 312, 314, respectively. Forexample, the first and second rectifiers 316, 318 may output a currentto the capacitor 320 based on the state of the first and secondcontrollable switches 312, 314, respectively. The first and secondrectifiers 316, 318 may be any silicon-based semiconductor switch (e.g.,diodes). The first and second controllable switches 312, 314 may be anysemiconductor transistors (e.g., MOSFETs). The first and secondcontrollable switches 312, 314 also may be operably connected to theregulator 322. In this regard, the regulator 322 may be configured toswitch each of the first and second controllable switches 312, 314between a conducting state and a non-conducting state.

As discussed above in relation to FIG. 10, the power supply 210 mayprovide power to the controller 214 of the DSR 30. The power supply 210may be operable to output a regulated voltage (e.g., a 24 VDC output) tothe controller 214. When the regulated voltage satisfies a predeterminedthreshold (e.g., if the regulated voltage is greater than the threshold,or is equal to or greater than the threshold), the regulator 322 mayswitch the first and second controllable switches 312, 314 to theconducting state. In one embodiment, the predetermined threshold may bewithin a range from about 23.9V to about 24.1V. This predeterminedthreshold may be a standard design power supply voltage for the system.When the first and second controllable switches 312, 314 are in theconducting state, the output current from the first and secondrectifiers 316, 318 may be shunted. For example, the second currentreceived from the current transformer 208 may flow through the first andsecond controllable switches 312, 314 such that the power supply 210 isshorted and no or very little current flows through the first and secondrectifiers 316, 318. As discussed above, the capacitor 320 may receivecurrent from the first and second rectifiers 316, 318. As such, when theoutput current from the first and second rectifiers 316, 318 is shunted,the capacitor 320 may begin to discharge.

When the regulated voltage no longer satisfies the predeterminedthreshold (e.g., if the regulated voltage drops below the predeterminedthreshold), the regulator 322 switches the first and second controllableswitches 312, 314 to the non-conducting state. When the first and secondcontrollable switches 312, 314 are in the non-conducting state, thesecond current from the current transformer 208 may flow through thefirst and second rectifiers 316, 318. As such, the capacitor 320 mayreceive the output current from the first and second rectifiers 316, 318and may begin to charge. In turn, the output voltage of the power supply210 is regulated. In one embodiment, the regulator 322 may have anoperating frequency substantially higher than the current frequency onthe power line 16.

As discussed above in relation to FIG. 10, the current monitor 212 maybe operable to measure the current on the power line 16 (at the DSR 30)and communicate the measured current to the controller 214. Oneembodiment that may be used as the current monitor 212 is illustrated inFIG. 11B. The current monitor 212 of FIG. 11B may be operably connectedto the current transformer 208, and furthermore may be configured tomeasure the second current from the current transformer 208. The currenttransformer 208 may be operable to output the second current to thepower supply 210 through the current monitor 212. In this regard, thecontroller 214 may be configured to switch the current transformer 208from a first state to a second state. The first state may include thecurrent transformer 208 outputting the second current to the powersupply 210. When the current transformer 208 is in the first state, thepower supply 210 outputs the regulated voltage. The second state mayinclude a measurement of the second current via the current monitor 212.When the current transformer 208 is in the second state, the first andsecond controllable switches 312, 314 are in the conducting state andthe power supply 210 is shorted such that the second current flowsthrough the first and second controllable switches 312, 314. Shuntingthe power supply 210 operation while the current transformer 208 is inthe second state may remove any contribution of high-frequency switchingnoise, or other non-linearity associated with the power supply 210operation from the measurement of the second current. As a result, thequality and signal-to-noise ratio of the current monitor 212 may beincreased.

As illustrated in FIG. 11B, the controller 214 may include a logicalsumming device 332. The logical summing device 332 may be any simplelogic element or programmable logic device such as a programmable logicarray and a field-programmable gate array, to name a few. The logicalsumming device 332 may be configured to output a control signal. Whenthe control signal is active, the current transformer 208 is in thesecond state and the first and second controllable switches 312, 314 arein the conducting state. This is true even if the regulated voltage nolonger satisfies the predetermined threshold. In other words, when thepower supply 210 is in normal operation, and the regulated voltage nolonger satisfies the predetermined threshold, the first and secondcontrollable switches 312, 314 are switched to the non-conducting state.However, if the control signal from the logical summing device 332 isactive, the first and second controllable switches 312, 314 remain inthe conducting state, resulting in the absence of influence of controlpulses from the regulator 322 on the measurement of the second current.In this regard, the control signal from the logical summing device 332may facilitate the measurement of the second current via the currentmonitor 212. When the current monitor 212 measures the second current,the second current may have a signal-to-noise ratio of at least about 48dB.

The current monitor 212 may include an instrumental current transformer342, a burden resistor 344, a differential amplifier 346, a comparator348, and/or an analog-to-digital converter 349. The instrumental currenttransformer 342 may be operably connected to the current transformer 208and configured to reduce the second current from the current transformer208 to a third current. This third current may be less than the secondcurrent and proportional to the second current. This third current maybe less than the first current (i.e., the current of the power line 16),and is proportional to the first current. The burden resistor 344 may beoperably connected to the output of the instrumental current transformer342 such that a voltage develops on the burden resistor 344. The voltageon the burden resistor 344 is proportional to the third current, andthus to the first and second currents. The differential amplifier 346may be operably connected to the burden resistor 344 and may beconfigured to convert and/or amplify the voltage on the burden resistor344. The analog-to-digital converter 349 may be operably connected tothe differential amplifier 346 and the controller 214. As such, thedifferential amplifier 346 may send the analog-to-digital converter 349an analog signal representative of the voltage on the burden resistor344. In turn, the analog-to-digital converter 349 may be configured toconvert the analog signal from the differential amplifier 346 into adigital signal from which the controller 214 can determine the currenton the power line 16. As will be discussed in more detail below, thecomparator 348 may be operably connected to the differential amplifier346 and the controller 214, and may be configured to send an interruptsignal to the controller 214.

FIG. 12A illustrates one embodiment for the above-noted fault protectionsystem 220 of the DSR 30. The fault protection system 220 includes thepower supply 210 (FIGS. 10 and 11A), the current monitor 212 (FIGS. 10and 11 B), a voltage detection circuit 356, the first device 202 (e.g.,a transformer that uses the core assembly 50) addressed above (FIG. 10),and the first electrical switch 204 (e.g., an SCR; FIG. 10). The faultprotection system 220 may include a plurality of different bypasssequences that are separately executable. The plurality of differentbypass sequences may be executed to activate the first electrical switch204 to short the first device 202. As discussed above, the firstelectrical switch 204 may be operable to pass an overcurrent. When thefirst electrical switch 204 is activated, the first electrical switch204 may pass the overcurrent. In this regard, the plurality of differentbypass sequences may be separately executed to protect the DSR 30 fromovercurrent and/or fault conditions. The plurality of different bypasssequences may include first, second, and third bypass sequences.

The first bypass sequence may include the controller 214 activating thefirst electrical switch 204 (e.g., an SCR) to short the first device 202(e.g., a transformer that uses the core assembly 50) based upon thecontroller 214 determining that an output from the current monitor 212satisfies a first predetermined threshold (e.g., if the output isgreater than the threshold, or is equal to or greater than thethreshold). For example and as discussed above, the current monitor 212may include/utilize one or more of the differential amplifier 346, theanalog-to-digital converter 349, and the controller 214. As such, theoutput from the differential amplifier 346 may be an analog signal(e.g., a voltage signal) that gets sent to the analog-to-digitalconverter 349, where it is converted and sent to the controller 214which determines if the analog signal satisfies the first predeterminedthreshold. In this case, if the first predetermined threshold issatisfied, the controller 214 may activate the first electrical switch204 to short the first device 202.

The second bypass sequence may include the comparator 348 sending acommunication (e.g., an interrupt signal) to the controller 214,indicating that the output from the current monitor 212 satisfies asecond predetermined threshold. For example and as discussed above, thecomparator 348 may be operably connected with the differential amplifier346 and the controller 214. As such, the output from the current monitor212 may be the analog signal from the differential amplifier 346. Thecomparator 348 may receive the analog signal (e.g., a voltage signal) atits input, and determine if the voltage signal satisfies the secondpredetermined threshold. If the voltage signal satisfies the secondpredetermined threshold, the comparator 348 may send the interruptsignal to the controller 214. In this case, the controller 214 mayactivate the first electrical switch 204 (e.g., an SCR) to short thefirst device 202 (e.g., a transformer that uses the core assembly 50),in response to receiving the interrupt signal from the comparator 348.In other words, the interrupt signal may prompt the controller 214 toactivate the first electrical switch 204. In order to activate the firstelectrical switch 204, the controller 214 may send a series ofelectrical pulses to the first electrical switch 204 such that the firstelectrical switch 204 begins conducting.

The output of the differential amplifier 346, i.e., the analog signal,may be representative of the current on the power line 16. For example,when the analog signal satisfies the first predetermined threshold, thismay indicate that the current on the power line 16 is at least about1100 Amps. In another example, when the analog signal satisfies thesecond-predetermined threshold, this may indicate that the current onthe power line 16 is at least about 1800 Amps. In other examples, thefirst and second predetermined thresholds may be selected based onspecific applications of the fault protection system 220 of the DSR 30relative to a given installation. The first and second predeterminedthresholds may be selected to be above expected normal operating currentlimits on the power line 16. In other words, the first and secondpredetermined thresholds may be any value suitable to enable executionof the first and second bypass sequences to protect the DSR 30 fromovercurrent and/or fault conditions.

The third bypass sequence may include the voltage detection circuit 356(e.g., a crowbar circuit) activating the first electrical switch 204(e.g., an SCR) to short the first device 202 when a detected voltagesatisfies a third predetermined threshold. The detected voltage may be avoltage of the first device 202. For example and as discussed above, thefirst device 202 may be a single turn transformer including windings144, 174 on the core assembly 50 (e.g., the secondary of a single turntransformer). As such, the detected voltage may be a voltage present onthe secondary windings 144, 174 of the core assembly 50. In oneembodiment, the third predetermined threshold may be at least about 1800volts. The third predetermined threshold may be selected based onspecific applications of the fault protection system 220 of the DSR 30relative to a given installation. The third predetermined threshold maybe selected based on the operational limits of the electronic componentswithin the fault protection system 220 of the DSR 30 and/or the numberof secondary windings 144, 174 of the core assembly 50. In other words,the third predetermined threshold may be any value suitable to enableexecution of the third bypass sequence to protect the DSR 30 fromovercurrent and/or fault conditions.

A secondary function of the fault protection system 220 may includeprotection of the second electrical switch 206 addressed above (e.g., acontact relay; FIG. 10). The second electrical switch 206 may beoperably connected to the controller 214 and the first device 202. Thecontroller 214 may be configured to switch the second electrical switch206 between an open position and a closed position in order to switchthe DSR 30 between bypass and injection modes of operation as discussedabove. During such a change of position, the second electric switch 206may be vulnerable to damage from electric arc and/or excessive currentsthrough its contact surfaces. This damage may be minimized by externallyshunting the contacts of the second electrical switch 206 during anysuch change of position, where the duration of the change of positionmay be within a range from about one millisecond to about one second.The secondary function of the fault protection system 220 may beactivated by the controller 214 issuing a series of electrical pulses tothe first electric switch 204 during the period when the second electricswitch 206 is changing positions. In turn, the first electrical switch204 may enter a conducting state, thereby shunting the contacts of thesecond electric switch 206.

For the same purpose, when the first electrical switch 204 is activated(e.g., when any of the first, second, or third bypass sequences isexecuted), the second electrical switch 206 remains in either the openposition or the closed position. For example, if the second electricalswitch 206 is in the open position (e.g., the DSR 30 is in injectionmode) when the first electrical switch 204 (e.g., an SCR) is activated,the second electrical switch 206 remains in the open position during theexecution of any of the first, second, or third bypass sequences. Inanother example, if the second electrical switch 206 is in the closedposition (e.g., the DSR 30 is in bypass mode) when the first electricalswitch 204 is activated, the second electrical switch 206 remains in theclosed position during the execution of any of the first, second, orthird bypass sequences.

The first bypass sequence may have a first response time, the secondbypass sequence may have a second response time, and the third bypasssequence may have a third response time. The first response time may bethe amount of time it takes for the controller 214 to determine that theoutput from the current monitor 212 satisfies the first predeterminedthreshold. For example, the analog-to-digital converter 349 may receivethe output from the current monitor 212 while the controller 214 isperforming another function, which may result in a first response time.In another example, the controller 214 may process the output from thecurrent monitor 212 immediately upon receiving it, which may result in afirst response time that is different than the first response time inthe first example. The second response time may be the amount of time ittakes for the comparator 348 to determine that the output from thedifferential amplifier 346 satisfies the second predetermined threshold.The third response time may be the amount of time it takes for thevoltage detection circuit 356 to determine that the detected voltagesatisfies the third predetermined threshold.

The first response time may be faster than the second response time andthe third response time, and the second response time may be faster thanthe third response time. For example, the controller 214 may determinethat the output from the current monitor 212 satisfies the firstpredetermined threshold before the comparator 348 determines that theoutput from the differential amplifier 346 satisfies the secondpredetermined threshold and before the voltage detection circuit 356determines that the detected voltage satisfies the third predeterminedthreshold. As another example, the comparator 348 may determine that theoutput from the differential amplifier 346 satisfies the secondpredetermined threshold before the voltage detection circuit 356determines that the detected voltage satisfies the third predeterminedthreshold. The second response time may be faster than the firstresponse time and the third response time. For example, the comparator348 may determine that the output from the differential amplifier 346satisfies the second predetermined threshold before the controller 214determines that the output from the current monitor 212 satisfies thefirst predetermined threshold and before the voltage detection circuit356 determines that the detected voltage satisfies the thirdpredetermined threshold. The third response time may be faster than thefirst response time and the second response time. For example, thevoltage detection circuit 356 may determine that the detected voltagesatisfies the third predetermined threshold before either the controller214 or the comparator 348 determine that the output from the currentmonitor 212 satisfies the first or the second predetermined thresholds.

If the first bypass sequence is executed, the second and third bypasssequences may not be executed. Similarly, the second bypass sequence maybe executed if the first bypass sequence is not executed. The firstbypass sequence may not be executed when the output from the currentmonitor 212 is not processed by the controller 214 and/or if the secondresponse time is faster than the first response time. The third bypasssequence may be executed if the first and second bypass sequences arenot executed and/or if the third response time is faster than the firstand second response times.

One embodiment of a protocol for protecting the DSR 30 is presented inFIG. 12B and is identified by reference numeral 360. The protocol 360generally includes the steps for detecting a fault current and executinga plurality of different bypass sequences to protect the DSR 30 fromdamage. As current flows through the power line 16, the currenttransformer 208 produces a reduced current that is proportional to thecurrent of the power line 16 (step 361) and the voltage detectioncircuit 356 monitors the voltage of the first device 202 (step 362). Thereduced current produced by the current transformer 208 may be measuredby the controller 214 (step 363) or the comparator 348 (step 366). Step363 includes the controller 214 determining if the reduced currentsatisfies the first predetermined threshold (step 364). If the reducedcurrent does not satisfy the first predetermined threshold, step 363 isrepeated, i.e., the controller 214 continues measuring the reducedcurrent produced by the current transformer 208. If the reduced currentdoes satisfy the first predetermined threshold, the first bypasssequence 371 (FIG. 12C) is executed (step 365).

In step 366 of the protocol 360 of FIG. 12B, the comparator 348 measuresthe reduced current produced by the current transformer 208. Step 366includes the comparator 348 determining if the reduced current satisfiesthe second predetermined threshold (step 367). If the reduced currentdoes not satisfy the second predetermined threshold, step 366 isrepeated, i.e., the comparator 348 continues measuring the reducedcurrent produced by the current transformer 208. If the reduced currentdoes satisfy the second predetermined threshold, the second bypasssequence 380 (FIG. 12D) is executed (step 368).

In step 362 of the protocol 360 of FIG. 12B, the voltage detectioncircuit 356 monitors the voltage of the first device 202. Step 362includes the voltage detection circuit 356 determining if the voltage ofthe first device 202 satisfies the third predetermined threshold (step369). If the voltage does not satisfy the third predetermined threshold,step 362 is repeated, i.e., the voltage detection circuit 356 continuesto monitor the voltage of the first device 202. If the voltage doessatisfy the third predetermined threshold, the third bypass sequence 390(FIG. 12E) is executed (step 370).

With reference now to FIG. 12C, one embodiment of the first bypasssequence 371 is presented. The first bypass sequence 371 may include thesteps of monitoring the current of the power line 16 (step 372),assessing whether the line current on the power line 16 satisfies thefirst predetermined threshold (step 373), and shorting the first device202 in response to identification of satisfaction of the firstpredetermined threshold (step 375). Step 373 may include the step ofmeasuring the current via the analog-to-digital converter 349 (step374). Step 375 may include the step of activating the first electricalswitch 204 (step 376). Step 376 may include the step of sending a seriesof electrical pulses to the first electrical switch 204 such that thefirst electrical switch 204 begins conducting (step 377).

FIG. 12D illustrates one embodiment of the second bypass sequence 380.The second bypass sequence 380 may include the steps of monitoring thecurrent of the power line 16 (step 381), assessing whether the linecurrent on the power line 16 satisfies the second predeterminedthreshold (step 382), sending an interrupt signal to the controller 214in response to identification of satisfaction of the secondpredetermined threshold (step 384), and shorting the first device inresponse to identification of satisfaction of the second predeterminedthreshold (step 385). Step 382 may include the step of measuring thevoltage input to the comparator 348 (step 383). Step 385 may include thestep of activating the first electrical switch 204 (step 386). Step 376may include the step of sending a series of electrical pulses to thefirst electrical switch 204 such that the first electrical switch 204begins conducting (step 387).

With reference now to FIG. 12E, one embodiment of the third bypasssequence 390 is presented. The third bypass sequence 390 may include thesteps of monitoring the voltage of the first device 202 (step 391),assessing whether the voltage satisfies the third predeterminedthreshold (step 392), and shorting the first device 202 in response toidentification of satisfaction of the third predetermined threshold(step 394). Step 392 may include the step of measuring the voltage ofthe first device 202 via the voltage detection circuit 356 (step 393).Step 394 may include the step of activating the first electrical switch204 (step 395). Step 395 may include the step of outputting the voltageof the first device 202 to the input of the first electrical switch 204via the voltage detection circuit 356 (step 396). In one embodiment, thesecond bypass sequence 380 (FIG. 12D) is executed when the first bypasssequence 371 (FIG. 12C) is not executed. The first bypass sequence 371(FIG. 12C) may not be executed when the current from the power line 16is not measured by the analog-to-digital converter 349. In oneembodiment, the third bypass sequence 390 is executed if neither thefirst bypass sequence 371 (FIG. 12C) nor the second bypass sequence 380(FIG. 12D) are executed.

FIG. 13A illustrates one embodiment of a power transmission system 400,or more generally a distributed control architecture for use by such apower transmission system. The power transmission system 400 includes atleast one power line 16 (three shown in the illustrated embodiment). Oneor more power lines 16 may be supported by a plurality of towers 14 thatare spaced along the length of the power line(s) 16. As in the case ofFIG. 1, the power transmission system 400 of FIG. 13A may include one ormore electrical power sources 12 (not shown) and one or more electricalloads 22 (not shown).

A plurality of DSRs 30 are installed on a given power line 16—multiplepower lines 16 each may have multiple DSRs 30 installed thereon. One ormore DSR array controllers 440 may be mounted on each power line 16 thatincorporates DSRs 30. Alternatively, a given DSR array controller 440could be mounted on a tower 14. In any case, each DSR array controller440 may be associated with a dedicated power line section 18 of thepower line 16. A given power line section 18 could have a single DSRarray controller 440, or a given power line section 18 could have aprimary DSR array controller 400, along with one or more backup DSRarray controllers 440.

Any number of DSR array controllers 440 may be associated with a givenpower line 16. A given power line 16 may be defined by one or more powerline sections 18 of the same length, by one or more power line sections18 of different lengths, or both (e.g., a power line section 18 is notlimited to a portion of a given power line 16 that spans betweenadjacent towers 14 as shown in FIG. 13A; a given power line 16 may bedivided up in any appropriate manner into multiple power line sections18, each of which may have one or more DSR array controllers 440 thatare dedicated to such a power line section 18).

One or more DSRs 30 are mounted on each power line section 18 of a givenpower line 16. Any appropriate number of DSRs 30 may be mounted on eachpower line section 18. The various DSRs 30 that are mounted on a givenpower line section 18 define what may be referred to as a DSR array 410.Each DSR array 410 may have one or more DSR array controllers 440 thatare dedicated to such a DSR array 410 (e.g., multiple controllers 440may be used for any given DSR array 410 to provide redundancy). In oneembodiment, a given DSR array controller 440 is only associated with oneDSR array 410. As such, one or more DSR array controllers 440 and eachDSR 30 of their dedicated DSR array 410 may be associated with the samepower line section 18. It should be appreciated that DSRs 30 need not beplaced along the entire length of a given power line 16 (although suchcould be the case), and as such there may be a gap between one or moreadjacent pairs of power line sections 18 that each have an associatedDSR array 410.

Each DSR 30 in a given DSR array 410 only communicates (directly orindirectly) with one or more DSR array controllers 440 that are assignedto the DSR array 410 (e.g., the primary DSR array controller 440 for theDSR array 410 and any redundant or backup DSR array controllers). Agiven DSR array controller 440 could communicate directly with each DSR30 in its associated DSR array 410. Another option would be to utilize arelay-type communication architecture, where a DSR array controller 440could communicate with the adjacent-most DSR 30 on each side of the DSRarray controller 440, and where the DSRs 30 could then relay thiscommunication throughout the remainder of the DSR array 410 on the sameside of the DSR array controller 440 (e.g., DSRs 30 in a given DSR array410 could relay a communication, from DSR 30-to-DSR 30, toward and/oraway from the associated DSR array controller 440).

DSR array controllers 440 associated with multiple DSR arrays 410communicate with a common DSR server 420 of the power transmissionsystem 400. Each of these DSR array controllers 440 could communicatedirectly with this DSR server 420. Alternatively, the DSR server 420could directly communicate with one or more DSR array controllers 440,and these DSR array controllers 440 could then relay the communicationto one or more other DSR array controllers 440 in the power transmissionsystem 400. It should also be appreciated that the power transmissionsystem 400 could incorporate one or more backup DSR servers (not shown),for instance to accommodate a given DSR server 420 going “off-line” forany reason. In any case, the DSR server 420 in turn communicates withwhat may be characterized a utility-side control system 430.Representative forms of the utility-side control system 430 includewithout limitation an energy management system (EMS), a supervisorycontrol and data acquisition system (SCADA system), or market managementsystem (MMS).

The power transmission system 400 could utilize any appropriate numberof DSR servers 420. A single DSR server 420 could communicate with agiven utility-side control system 430. Another option would be to havemultiple DSR servers 420 that each communicate with a commonutility-side control system 430. The power transmission system 400 couldalso utilize any appropriate number of utility-side control systems 430,where each utility-side control system 430 communicates with one or moreDSR servers 420.

A given DSR server 420 may be characterized as providing an interfacebetween a utility-side control system 430 and a plurality of DSR arraycontrollers 440 for multiple DSR arrays 410. A DSR server 420 mayreceive a communication from a utility-side control system 430. Thiscommunication may be in any appropriate form and of any appropriatetype. For instance, this communication could be in the form of a systemobjective, a command, a request for information, or the like (e.g., tochange the inductance on one or more power lines 16 by a stated amount;to limit the current on one or more power lines 16 to a stated amount;to limit the power flow on one or more power lines 16 to a statedamount; to set a temperature limit for one or more power lines 16).

The DSR array controllers 440 may send information on theircorresponding power line section 18 to a DSR server 420. The DSR server420 in this case may consolidate this information and transmit the sameto the utility-side control system 430 on any appropriate basis (e.g.,using a push-type communication architecture; using a pull-typecommunication architecture; using a push/pull type communicationarchitecture). The DSR server 420 may also store information receivedfrom the various DSR array controllers 440, including information fromthe DSR array controllers 440 that has been consolidated by the DSRserver 420 and at some point in time transmitted to an utility-sidecontrol system 430.

Each DSR array controller 440 may be characterized as a “bridge” betweena DSR server 420 (and ultimately a utility-side control system 430) andits corresponding DSR array 410. For instance, one communication schememay be used for communications between a DSR array controller 410 andthe DSRs 30 of its DSR array 410, and another communication scheme maybe used for communications between this same DSR array controller 410and the DSR server 420. In this case, a DSR array controller 410 mayrequire two different interfaces—one interface/communication module forcommunicating with the DSRs 30 of its DSR array 410, and anotherinterface/communication module for communicating with a DSR server 420.

As noted, FIG. 13A may be characterized as a distributed controlarchitecture for a power transmission system (or as a power transmissionsystem with a distributed control architecture). In this regard,consider the case where the utility-side control system 430 sends acommunication to a DSR server 420. The DSR server 420 mayrepackage/translate/reformat this communication, but in any case sends acorresponding communication to one or more DSR array controllers 440.Each such DSR array controller 440 that receives such a communicationmakes a determination as to the modal configuration for each DSR 30 inits corresponding DSR array 410 (i.e., determines whether a given DSR 30should be in a first or bypass mode, or whether this DSR 30 should be ina second or injection mode, and this may be undertaken for each DSR 30in its corresponding DSR array 410). Notably, the communication that isreceived by the DSR array controller 440 does not itself indicate as towhat the modal configuration should be for each DSR 30 in the DSR array410 for the recipient DSR array controller 440. As such, each DSR arraycontroller 440 must have sufficient intelligence so as to be able to beable to make this determination on its own.

FIG. 13B presents a representative configuration for a DSR arraycontroller 440 that may be utilized by the power transmission system 400of FIG. 13A. The DSR array controller 440 includes a housing 442.Preferably, the housing 442 allows the DSR array controller 440 to bemounted on a power line 16 without having to break the power line 16(e.g., by using detachably connectable housing sections at leastgenerally of the type discussed above in relation to the DSR 30).Moreover, preferably the housing 442 is configured to reduce thepotential for Corona discharges.

The DSR array controller 440 includes a current transformer 444 that isdisposed within the housing 442 and that derives power from the powerline 16 to power electrical components of the DSR array controller 440.Various sensors may be utilized by the DSR array controller 440, such asa fault current sensor 446 and a temperature sensor 448. Moreover, theDSR array controller 440 utilizes a processing unit 454 (e.g., definedby one or more processors of any appropriate type, and utilizing anyappropriate processing architecture).

FIG. 13C presents a functional schematic that may be implemented by aDSR array controller 440. The DSR array controller 440 includes theabove-noted processing unit 454. Memory 452 (e.g., any appropriatecomputer readable storage medium) may be operatively interconnected withthe processing unit 454. The memory 452 may be of any appropriate typeor types, and may utilize any appropriate data storage architecture(s).One or more sensors 456 (e.g. the above-noted fault current sensor 446;the above-noted temperature sensor 448) may also be operativelyinterconnected with the processing unit 454.

One or more antennas 450 may be utilized by the DSR array controller 440for communicating with the DSRs 30 in its corresponding DSR array 410.Any appropriate type of antenna 450 may be utilized by the DSR arraycontroller 440, including a cavity-backed slot antenna of the typeutilized by the DSRs 30. Multiple antennas 450 could also be used tocommunicate with the DSRs 30 in its corresponding DSR array 410,including where two antennas 450 are incorporated by the DSR arraycontroller 440 in the same manner as discussed above with regard to theDSRs 30 (e.g., an antenna 450 may be provided on each end of the DSRarray controller 440). As noted, the DSR array controller 440 may useone communication scheme (e.g., a first communication scheme) forcommunicating with the DSRs 30 of its DSR array 410.

The DSR array controller 440 also communicates with the utility-sidecontrol system 430 through the DSR server 420 in the embodiment of FIG.13A. In this regard, the DSR array controller 440 may include acommunications module 466 of any appropriate type and an interface 460.If the communications module 466 provides for wireless communicationswith the DSR server 420, the DSR array controller 440 may require one ormore antennas of any appropriate type. For example, the communicationsmodule may be at least one of an Ethernet adapter, a cellular modem, anda satellite modem, to name a few. In another example, the interface 460may be part of the processing unit 454 and may include at least one of aSPI bus, UART, and a 12C serial bus, to name a few. In any case, the DSRarray controller 440 may use another communication scheme (e.g., asecond communication scheme) for communicating with the DSR server 420.In one embodiment, the DSR array controller 440 uses differentcommunication schemes for communications with the DSR array 410 and theDSR server 420. It could be appreciated that a dedicated antenna(s) maybe required for communications with the DSRs 30 of the corresponding DSRarray 410, and that a dedicated antenna(s) may be required forcommunications with the DSR server 420. However, it may be possible thata common antenna(s) may be used to communicate with both the DSRs 30 ofthe corresponding DSR array 410 and with the DSR server 420.

The DSR array controller 440 may also incorporate a power supply 458 ofany appropriate type, and that is operatively interconnected with theabove-noted current transformer 444 (FIG. 13B). The power supply 458 mayreceive a current flow from the current transformer 444, and may providepower to one or more of the processing unit 454, the memory 452, theantenna(s) 450, one or more antennas associated with the communicationmodule 466 (for communicating with the DSR server 420), one or moresensors 456, or any combination thereof.

FIG. 13D presents one embodiment of a first data structure 480 (e.g., alookup table) that may be stored/reside in the memory 452 of a given DSRarray controller 440. The first data structure 480 may utilize anyappropriate data storage architecture. Generally, for each of aplurality of system contingencies or conditions 482, the first datastructure 480 includes a corresponding model configuration for at leastone control objective for each DSR 30 associated with the DSR arraycontroller 440. Again, there are two “modal configurations” for the DSRs30. One modal configuration (e.g., a first modal configuration or firstmode) for each DSR 30 is where the DSR is disposed in a non-injection orbypass mode (e.g., where little or no reactance is being injected intothe corresponding power line 16 by the DSR 30, or more specifically intothe corresponding power line section 18 on which the DSR 30 is mounted).The other modal configuration (e.g., a second modal configuration orsecond mode) for each DSR 30 is where it is configured to injectreactance into the corresponding power line 16 (e.g., an injectionmode). The amount of reactance injected by a given DSR 30 when in itssecond modal configuration (or when in its second mode) is substantiallygreater than the amount of reactance, if any, that is injected by agiven DSR 30 when in its first modal configuration (or when in its firstmode).

The first data structure 480 includes a modal configuration for twodifferent control objectives for each DSR 30 that is associated with theDSR array controller 440 (three representative DSRs 30 being shown forpurposes of the first data structure 480 of FIG. 13D; each DSR 30 withinthe corresponding DSR array 410 would of course be included in the firstdata structure 480). The first data structure 480 presents both a powerfactor control modal configuration 484 (one control objective) and alow-frequency oscillation control modal configuration 486 (a differentcontrol objective) for each DSR 30 associated with the DSR arraycontroller 440, and for each system condition or contingency 482. Anynumber of control objectives may be stored in the first data structure480, including a single control objective or any appropriate number ofmultiple control objectives.

The system conditions or contingencies that are loaded into the firstdata structure 480 may represent at least some or all of thepermutations for a power transmission system in relation to each powersource utilized by the power transmission system (whether on line or offline), the load level presently imposed on the system, the operatingstatus of the transmission lines forming the interconnected grid, theoperating status of the transformers and substation equipment supportingthe operation of the transmission lines forming the interconnected grid,or any combination of the above that combine to create a normal,abnormal or emergency operating condition for the grid. The same systemconditions or contingencies may be loaded into the memory 452 of one ormore DSR array controller 440. In one embodiment, a set of DSR arraycontrollers 440 will have the same system conditions or contingenciesloaded into their corresponding memory 452. However, each DSR arraycontroller 440 will have its own modal configuration for each of itsDSRs 30, and for each control objective. It should be appreciated thatthe first data structure 480 for each DSR array controller 440 may beupdated without having to dismount the DSR array controller 440 from itscorresponding power line 16 (e.g., using the built-in communicationcapabilities of the DSR array controllers 440)

One embodiment of an operations protocol for the power transmissionsystem 400 of FIG. 13A is presented in FIG. 13E and is identified byreference numeral 500. The utility-side control system 430 sends anoperations objective communication to the DSR server 420 (step 502).This operations objective communication may be of any appropriate type.The DSR server 420 may translate this communication from theutility-side control system 430 into an appropriate DSR format (step504). In any case, the DSR server 420 sends a correspondingcommunication to the relevant DSR array controllers 440 (step 506). Eachof the DSR array controllers 440 will independently determine the modalconfiguration for the DSRs 30 in its corresponding DSR array 410 basedupon receipt of this communication (step 508). The communicationassociated with step 506 does not itself indicate the modalconfigurations that are determined by step 508. Thereafter, the DSRarray controllers 440 may send a modal communication to one or more ofthe DSRs 30 in its corresponding DSR array 410 (step 510), and the DSRs30 may be operated in accordance with any modal communication that hasbeen received (step 514). It should be appreciated that the protocol 500could be configured such that a modal communication is sent by a givenDSR array controller 440 to each of its corresponding DSRs 30 (step510), or a given DSR array controller 440 could be configured to send amodal communication (step 510) only to those associated DSRs 30 thathave been determined to be in need of a modal change in accordance withstep 508.

The operations protocol 500 of FIG. 13E may include what may becharacterized as an optional “temperature override” feature. In thisregard, step 512 of the protocol 500 is directed to determining if anexcessive temperature condition exists on any given power line section18 (e.g., determining whether an operating temperature meets or exceedsa predetermined temperature threshold, and which may be undertaken inany appropriate manner). Each power line section 18 may be monitored forthe existence of an excessive temperature condition. This monitoring maybe undertaken by the DSR array controller(s) 440 and/or the DSRs 30 forsuch a power line section 18. In any case and in the event that such anexcessive temperature condition has been determined to exist, theprotocol 500 may be configured to execute step 516. Step 516 is directedto configuring one or more of the DSRs 30 on the subject power linesection 18 (with an excessive temperature condition) to injectinductance into this power line section 18. Injecting inductance into agiven power line section 18 that is experiencing an excessivetemperature condition should reduce the current flow through such apower line section 18, which in turn should reduce its operatingtemperature. It should be appreciated that steps 512 and 516 on thenoted temperature override feature may be implemented at any appropriatelocation within the protocol 500. Moreover, it should be appreciatedthat the temperature override logic could be incorporated by the DSRarray controllers 440 (which would then send an appropriatecommunication to the DSRs 30 of their corresponding DSR array 410, suchthat step 516 would be executed by the individual DSRs 30 upon receivingsuch a communication from their corresponding DSR array controller(s)440), that the temperature override logic could be incorporated by theindividual DSRs 30 of each DSR array 410 (e.g., such that eachindividual DSR 30 could independently determine when step 516 should beexecuted), or both.

One embodiment of an operations protocol for addressing systemconditions or contingencies is illustrated in FIG. 13F and is identifiedby reference numeral 520. Step 522 of the protocol 520 is directed tosending or transmitting a system condition or system contingencycommunication to one or more DSR array controllers 440 of the powertransmission system 400. This system condition/contingency communicationmay come directly from the utility-side control system 430 or throughthe DSR server 420. In any case, one or more DSR array controllers 440may receive the system condition/contingency communication (step 524).Each DSR array controller 440 will then retrieve the modal configurationinformation from the first data structure 480 for all

DSRs 30 in its corresponding DSR array 410 (step 526). That is, each DSRarray controller 440 will locate the system condition/contingency withinits first data structure 480, and will then retrieve the associatedmodal configuration for each DSR 30 in its DSR array 410 for theassociated control objective. Each DSR array controller 440 may thensend a modal communication to each DSR 30 in its corresponding DSR array410 (step 528) to specify whether a given DSR 30 should be in its firstor bypass mode, or whether this DSR 30 should be in its second orinjection mode. The controller 54 of a DSR 30 that receives such a modalcommunication from its corresponding DSR array controller 440 will thendispose the DSR 30 in the communicated mode pursuant to step 532 (eitherby switching the mode of the DSR 30, or maintaining the DSR 30 in itsthen current mode). It should be appreciated that the protocol 520 couldbe configured such that a modal communication is sent by a given DSRarray controller 440 to each of its corresponding DSRs 30 (step 528), ora given DSR array controller 440 could be configured to send a modalcommunication (step 528) only to those associated DSRs 30 that have beendetermined to be in need of a modal change based upon step 526.

The operations protocol 520 of FIG. 13F may include what may becharacterized as an optional “temperature override” feature. In thisregard, step 530 of the protocol 520 is directed to determining if anexcessive temperature condition exists on any given power line section18 (e.g., determining whether an operating temperature meets or exceedsa predetermined temperature threshold, and which may be undertaken inany appropriate manner). Each power line section 18 may be monitored forthe existence of an excessive temperature condition. This monitoring maybe undertaken by the DSR array controller(s) 440 and/or the DSRs 30 forsuch a power line section 18. In any case and in the event that such anexcessive temperature condition has been determined to exist, theprotocol 520 may be configured to execute step 534. Step 534 is directedto configuring one or more of the DSRs 30 on the subject power linesection 18 (with an excessive temperature condition) to injectinductance into this power line section 18. Injecting inductance into agiven power line section 18 that is experiencing an excessivetemperature condition should reduce the current flow through such apower line section 18, which in turn should reduce its operatingtemperature (assuming of course that current flow can be diverted to oneor more other power lines 16/power line sections 18). It should beappreciated that steps 530 and 534 on the noted temperature overridefeature may be implemented at any appropriate location within theprotocol 520. Moreover, it should be appreciated that the temperatureoverride logic could be incorporated by the DSR array controllers 440(which would then send an appropriate communication to the DSRs 30 oftheir corresponding DSR array 410, such that step 534 would be executedby the individual DSRs 30 upon receiving such a communication from theircorresponding DSR array controller(s) 440), that the temperatureoverride logic could be incorporated by the individual DSRs 30 of eachDSR array 410 (e.g., such that each individual DSR 30 couldindependently determine when step 534 should be executed), or both.

The operations protocol 520 of FIG. 13F assumes that the various DSRarray controllers 440 are able to receive system condition/contingencycommunications from the utility-side control system 430 and/or the DSRserver 420. That may not always be the case, and is accommodated by theoperations protocol that is set forth in FIG. 13G and that is identifiedby reference numeral 540. Step 542 of the protocol 540 is directed toassessing receipt of system condition/contingency communications. In theevent a predetermined number of DSR array controllers 440 are notreceiving system condition/contingency communications, the protocol 540proceeds from step 544 to step 546. Step 546 of the protocol 540 isdirected to the DSR array controllers 440 communicating with one anotherand sharing information regarding their corresponding power line section18. From this information, the present state systemcondition/contingency is derived (step 548). A derived systemcondition/contingency communication is then sent to the various DSRarray controllers 440 pursuant to step 550 of the protocol 540. Each DSRarray controller 440 will then retrieve the modal configurationinformation from the first data structure 480 for all DSRs 30 in itscorresponding DSR array 410 (step 552). That is, each DSR arraycontroller 440 will locate the system condition/contingency within itsfirst data structure 480 that corresponds to the derived systemcondition/contingency communication, and will then retrieve theassociated modal configuration for each DSR 30 in its DSR array 410 (andfor the associated control objective). Each DSR array controller 440 maythen send a modal communication to each DSR 30 in its corresponding DSRarray 410 (step 556) to specify whether a given DSR 30 should be in itsfirst or bypass mode, or whether this DSR 30 should be in its second orinjection mode. The controller 54 of a DSR 30 that receives such a modalcommunication from its corresponding DSR array controller 440 will thendispose the DSR 30 in the communicated mode pursuant to step 560 (eitherby switching the mode of the DSR 30, or maintaining the DSR 30 in itsthen current mode). It should be appreciated that the protocol 540 couldbe configured such that a modal communication is sent by a given DSRarray controller 440 to each of its corresponding DSRs 30 (step 556), ora given DSR array controller 440 could be configured to send a modalcommunication (step 556) only to those associated DSRs 30 that have beendetermined to be in need of a modal change based upon step 552.

The operations protocol 540 of FIG. 13G may include what may becharacterized as an optional “temperature override” feature. In thisregard, step 558 of the protocol 540 is directed to determining if anexcessive temperature condition exists on any given power line section18 (e.g., determining whether an operating temperature meets or exceedsa predetermined temperature threshold, and which may be undertaken inany appropriate manner). Each power line section 18 may be monitored forthe existence of an excessive temperature condition. This monitoring maybe undertaken by the DSR array controller(s) 440 and/or the DSRs 30 forsuch a power line section 18. In any case and in the event that such anexcessive temperature condition has been determined to exist, theprotocol 540 may be configured to execute step 562. Step 562 is directedto configuring one or more of the DSRs 30 on the subject power linesection 18 (with an excessive temperature condition) to injectinductance into this power line section 18. Injecting inductance into agiven power line section 18 that is experiencing an excessivetemperature condition should reduce the current flow through such apower line section 18, which in turn should reduce its operatingtemperature. It should be appreciated that steps 558 and 562 on thenoted temperature override feature may be implemented at any appropriatelocation within the protocol 540. Moreover, it should be appreciatedthat the temperature override logic could be incorporated by the DSRarray controllers 440 (which would then send an appropriatecommunication to the DSRs 30 of their corresponding DSR array 410, suchthat step 562 would be executed by the individual DSRs 30 upon receivingsuch a communication from their corresponding DSR array controller(s)440), that the temperature override logic could be incorporated by theindividual DSRs 30 of each DSR array 410 (e.g., such that eachindividual DSR 30 could independently determine when step 562 should beexecuted), or both.

Each DSR array controller 440 may incorporate any one of the protocols500, 520, and 540, or may incorporate any two or more of theseprotocols. For instance, each DSR array controller 440 could incorporateboth the protocol 500 of FIG. 13E and the protocol 520 of FIG. 13F. EachDSR array controller 440 could then determine the modal configurationfor each DSR 30 in its corresponding DSR array 410 based upon the typeof communication that is received. Another option would be for each DSRarray controller 440 to incorporate both the protocol 520 of FIG. 13Fand the protocol 540 of FIG. 13G. Each DSR array controller 440 could beconfigured to operate simultaneously in accordance with the protocol 520of FIG. 13F and the protocol 540 of FIG. 13G. That is, the protocol 520would be used to control a given DSR array control 440 until step 546 ofthe protocol 540 of FIG. 13G was reached, in which case the protocol 540would then be used to control a given DSR array controller 440.

A simplified version of a geomagnetically-induced current or GICmonitoring system is illustrated in FIG. 14 and is identified byreference numeral 600. The GIC monitoring system 600 is a line-mounteddevice—it is installed on a power line 16. Generally, the GIC monitoringsystem 600 is configured to monitor and/or identify the existence of ageomagnetically-induced current (which herein may be referred to as a“GIC”) on a power line 16, and furthermore is able to communicateinformation regarding a GIC on its corresponding power line 16 to one ormore other devices. As will be discussed in more detail below, the GICmonitoring system 600 may be installed on a power line 16 as astandalone unit. Another option would be to incorporate the GICmonitoring system 600 with another line-mounted device, such as theabove-described DSR 30.

The GIC monitoring system 600 includes a magnetic core 602 that at leastpartially surrounds a power line 16 (e.g., the magnetic core 602 mayextend less than a full 360° about the power line 16). The magnetic core602 may be composed of any suitable high permeability material. Althoughthe magnetic core 602 (e.g., collectively defined by core components620, 622, and 624, discussed below) is illustrated as having a round orcircular outer perimeter, other shapes may be appropriate. The magneticcore 602 may have an air gap 604 defined therein, and this air gap 604may be incorporated such that the magnetic core 602 does not completelysurround the power line 16 (i.e., the magnetic core 602 may beconfigured to not provide a closed perimeter about the power line 16). Amagnetic sensor 606 (e.g., a Hall effect sensor) may be positioned inthis air gap 604. The magnetic core 602 may be used to concentrate themagnetic flux, in the region surrounding the power line 16, within themagnetic core 602 and within the air gap 604 defined therein. This maygreatly increase the sensitivity (or gain) of the magnetic sensor 606 ascompared to a system without a magnetic core. It may also greatlyincrease the selectivity of the magnetic sensor 606, in that magneticfields from surrounding devices may be more easily ignored. By design,the magnitude of the magnetic field in the air gap 604 is proportionalto the magnitude of the current in the power line 16.

The magnetic sensor 606 may provide an output signal that may besupplied to a signal processing unit 608 (described further below) ofthe GIC monitoring system 600. The signal processing unit 608 mayprovide one or more signals representative of the GIC (at a minimum) toa communications interface 610, which may communicate with an antenna612 (the communications interface 610 and antenna 612 each may be partof the GIC monitoring system 600). A power supply 614 may be associatedwith the GIC monitoring system 600 in order to provide power to one ormore of its components.

The GIC monitoring system 600 is designed to sense DC or quasi-DCcurrents in the power line 16 (as will be discussed below, the GICmonitoring system 600 can also be configured to measure AC current inthe power line 16 as well, for instance for “on-line calibration”purposes). These currents may be sensed with the sensor 606 anddetermined by the signal processing unit 608. The communicationsinterface 610 and antenna 612 may be used to provide GIC information toone or more external devices (e.g., to send a GIC communication), forinstance using the communication architecture described above inconjunction with the DSR 30, DSR array controller 440, and othercomponents in the described network.

The magnetic core 602 may be designed in any fashion so as to provide anair gap into which a magnetic sensor can be placed. In one embodimentand as shown in FIGS. 15A and 15B, the magnetic core 602 is shown tohave three separate core components: an upper core component 620 and twolower core components 622, 624. In this case, the upper core component620 is shown to be generally semi-circular in configuration so as tosurround approximately 180° or one-half of the power line 16. The twolower core components 622 and 624 in this case are configured asgenerally a quarter of a circle in angular extent so as to surroundapproximately 90° or one quarter of the power line 16. Morespecifically, these two lower core components 622 and 624 each surroundjust less than 90° of the angular extent. By being just less than 90°,together they provide for the air gap 604 for the sensor 606.Optionally, one of the lower core components could be 90° or more inextent and the other lower core component could be an appropriate amountso that together the two components add up to an extent just less than180°, so as to create an air gap therebetween for the sensor 606. Asanother option, the air gap for the sensor 606 could be provided betweenthe upper and lower components of the magnetic core 602, and in suchcase there may only be one lower core component. As another option,there could be a single core component for the magnetic core 602 that isjust less than 360° in angular extent. Having a multi-section ormulti-piece magnetic core 602 (e.g., two or more components that may beseparately moved relative to one another) may facilitate installation ofthe GIC monitoring system 600 on the power line 16 (e.g., so as to notrequire a break in the power line 16 in order to install the magneticcore 602, although it may be possible to install a GIC monitoring system600, having a one-piece magnetic core 602 and with an appropriate airgap 604, on the power line 16 without requiring a break in the powerline 16).

Further detail on the signal processing unit 608 used by the GICmonitoring system 600 is provided in FIG. 16. The output signal from themagnetic sensor 606 may be a differential output signal provided on atwisted pair 628 of wires that are provided as an input to the signalprocessing unit 608. This twisted pair 628 may be connected to adifferential input of an A-to-D (A/D) converter 630. A device (notshown) for conditioning the signal (e.g., a “signal conditioner”), couldbe disposed between the magnetic sensor 606 and the A/D converter 630,for instance to improve the signal-to-noise ratio and which could bepart of the signal processing unit 608. In any case and after thedifferential analog signal is converted to a digital signal, it isprovided to each of an AC processing portion 632 and a DC processingportion 634 of the signal processing unit 608.

The AC processing portion 632 may include a high pass filter 636 toreduce the amount of DC (or lower frequency) signals. After filtering,the digital signal is provided to an RMS detector 638 which maydetermine a magnitude of the AC signal. The AC current magnitude signalis then provided to a ratio determining unit 640. A reference signal 642is also provided to the ratio determining unit 640. The reference signal642 may be an AC current magnitude that has been separately determinedby an external unit. For example, the AC current magnitude could beprovided from a current monitor 212 of the DSR 30 (described above). Inany case, the ratio determining unit 640 may provide an output signalbased on the ratio of the reference signal 642 to the AC currentmagnitude signal from the RMS detector 638. For example, if thereference signal 642 has a magnitude corresponding to 120 Amps and theAC current magnitude signal from the RMS detector 638 has a magnitudecorresponding to 100 Amps, then the output signal from the ratiodetermining unit 640 would have a magnitude corresponding to a ratio of1.2. As will be seen below, such a ratio can be used to increase thedetermined magnitude of the GIC by 20%.

The DC processing portion 634 of the signal processing unit 608 mayinclude a low pass filter 644 to filter out higher frequency signalssuch as AC currents in the 50 to 60 Hz range and higher-frequencyharmonics thereof. After filtering, the signal is provided to a meandetector 646 that determines the average or mean value of the DC (orquasi-DC) current. This mean value of the DC current is then provided toa multiplier 648 which also receives the ratio signal from the ratiodetermining unit 640. The two signals are multiplied together to providethe GIC signal 650. Continuing with the example from the previousparagraph, where the ratio determined was 1.2, if the mean value of theDC current determined by the mean detector 646 was 5 Amps, the GICsignal 650 would be 6 Amps. In this manner, the magnitude of the DCcurrent determined by the GIC monitoring system 600 is adjusted by theratio of the reference signal 642 to the determined AC currentmagnitude. In other words, the reference signal 642 is used as a “truth”or calibration for the proper current magnitude. It should beappreciated that calibration of the determined DC current magnitude(while the GIC monitoring system 600 is installed on a power line 16—an“on-line calibration”) may not be required in all instances (e.g.,factory calibration of the GIC monitoring system 600 may be sufficientin at least some instances). In this case, the signal processing unit608 of the GIC monitoring system 600 may eliminate the AC processingportion 632 (i.e., the GIC monitoring system 600 may then eliminate theratio determining unit 640 and the multiplier 648 discussed above).

The communications interface 610 for the GIC monitoring system 600 maybe a conventional communication interface capable of transmittinginformation to one or more remote devices. This interface 610 couldinclude a transmitter, a transmitter and receiver, or a transceiver. Theinterface 610 may work together with an antenna 612 of an appropriatetype. Further detail on an exemplary communications interface andantenna are provided above in conjunction with the discussion of the DSR30.

The power supply 614 for the GIC monitoring system 600 may be aconventional power supply capable of providing appropriate types ofpower to the remaining portions of the system 600. The power supply 614may harvest power from the power line 16 in a conventional manner. Anexemplary power supply is discussed above in conjunction with the DSR30.

As noted, the GIC monitoring system 600 could be incorporated intoanother line-mounted device. A variation of the above-discussed DSR 30is presented in FIG. 17 in the form of a DSR 30″. Correspondingcomponents of these two embodiments are identified by the same referencenumerals. Those corresponding components that differ are furtheridentified by a “double prime” designation in FIG. 17. Unless otherwisenoted, the DSR 30″ includes the same features as the DSR 30.

One difference between the DSR 30 and the DSR 30″ is that there is acurrent sensor 660 including an upper portion in the upper core assembly50″ and a lower portion in the lower core assembly 50″. There is also acircuit card 662 that may contain all or portions of one or more of thesignal processing unit 608, the communications interface 610 and antenna612, and the power supply 614. As can be appreciated, when the DSR 30″is assembled, the upper and lower components of the current sensor 660surround the power line 16 and leave an air gap 604 in which themagnetic sensor 606 is positioned (see FIG. 14). As the DSR 30″ mayinclude the above-noted current monitor 212, the GIC monitoring system600 could be configured to incorporate the noted optional AC processingportion 632 to provide for an on-line calibration functionality asdiscussed above.

A standalone version of the GIC monitoring system 600 is shown in FIG.18. A power line 16 is shown with a pair of line guards 20 locatedthereon. In this exploded view, upper and lower housing portions 670,672 are provided. Also included are an upper core segment 620, a lowercore segment 622, and a lower core segment 624, the latter two of whichprovide for an air gap 604 therebetween. The magnetic sensor 606 is alsoprovided for positioning within the air gap 604. A pair of circuit cardsis shown containing the signal processing unit 608 and thecommunications interface 610 and power supply 614. Although illustratedas provided on two circuit cards, these electronics could all be placedon one circuit card or on more than two circuit cards. It can beappreciated that when the GIC monitoring system 600 is assembled and theupper and lower housing portions 670, 672 are connected together, thecore components 620, 622, 624 are held in a position surrounding thepower line 16, with the exception of an air gap 604 into which themagnetic sensor 604 is positioned. As the GIC monitoring system 600shown in FIG. 18 does not include a separate current monitor, the GICmonitoring system 600 may be configured without the above-noted ACprocessing portion 632. However, a stand-alone GIC monitoring system 600could include a separate current monitor to accommodate on-linecalibration in accordance with the foregoing.

As can be seen, the GIC monitoring system 600 can be part of a unit withother components, such as part of a DSR 30″ (as shown in FIG. 17) or itcan be part of a standalone unit (as shown in FIG. 18). While the GICmonitoring system 600 described herein is only directed to monitoringand measuring GICs, it would be possible to attempt to control GICs in asimilar manner that AC line currents are controlled by injectingimpedance as described in conjunction with the DSR 30. As anotheralternative, the system 600 could be implemented without a magnetic core602, or with a completely different type of magnetic core. Some or allof the functionality of the signal processing unit 608 andcommunications interface 610 could be implemented in a microprocessor,or any other suitable form of electronics. It may be possible to provideinputs to the signal processing unit 608 so that the characteristics ofthe high pass filter 636 and low pass filter 644 can be varied. This mayinclude effectively eliminating the effects of filter 636 and 644.

One of the advantages of the GIC monitoring system 600 is that thesystem can be directly and easily mounted onto a power line 16 without abreak in the power line. Further, the system 600 can be powered from thepower line 16. It may be desirable to have an entire array of GICmonitoring systems 600 that are located throughout the powertransmission grid. With more systems, it may be possible to get moreaccurate measurements, and to measure GICs on power lines that are atdifferent orientations with respect to the Earth (e.g., with respect tolatitude and longitude lines).

A schematic of one embodiment of a power transmission system ispresented in FIG. 19 and is identified by reference numeral 700. Thepower transmission system 700 may be in the form of an electrical gridfor a region or territory (e.g., the electrical grid for the UnitedStates or any portion thereof). One characterization of the powertransmission system 700 is that it includes a plurality of zones (zone710 a-710l in the illustrated embodiment; more generally a “zone 710” inaccordance with the GIC monitoring protocol 750 that will be discussedbelow in relation to FIG. 20). The power transmission system 700 may beseparated into any appropriate number of zones 710.

A “zone 710” for purposes of the power transmission system 700 may becharacterized as encompassing a predetermined geographic area or regionof the power transmission system 700. Each zone 710 encompasses adifferent geographic region, although a given zone 710 could partiallyoverlap (geographically) with one or more other zones 710. In any case,each zone 710 of the power transmission system 700 includes at least onepower line 16, and more typically a plurality of power lines 16 (e.g.,part of a network or grid of power lines 16). The power lines 16 forpurposes of the power transmission system 700 may be of any appropriatetype, for instance in the form of a power transmission line (e.g.,higher capacity) or in the form of a distribution line (e.g., lowercapacity). A group of power lines 16 of the power transmission system700 may each extend from one common location to another common location,as well as along the same general path. This may be referred to as a“power transmission section” in accordance with the foregoing. In athree-phase power transmission system, each such “power transmissionsection” may have three different power lines 16 that are at threedifferent phases (and may optionally have a neutral line).

One or more zones 710 of the power transmission system 700 include atleast one GIC device 730. Each GIC device 730 may be in the form of theabove-described GIC monitoring system 600. One or more GIC devices 730could be installed on one or more power lines 16 within each zone 710,thereby encompassing a configuration for the power transmission system700 where at least one GIC device 730 is installed on each power line 16within each of its zones 710. Each GIC device 730 communicates (directlyor indirectly) with a utility-side control system 720 (FIG. 20) and overa communication link of any appropriate type. At least one-waycommunication is available between each GIC device 730 and theutility-side control system 720 (from a given GIC device 730 to theutility-side control system 720), although the power transmission system700 could be configured to allow for two-way communication between eachGIC device 730 and the utility-side control system 720.

The utility-side control system 720 for purposes of the powertransmission system 700 may be at least generally in accordance with theabove-described utility-side control system 430 of FIG. 13A (e.g., anenergy management system (EMS); a supervisory control and dataacquisition system (SCADA system); a market management system (MMS)). Inthe embodiment of FIG. 19, the utility-side control system 720 isillustrated as including a first utility-side control unit 720a and asecond utility-side control unit 720b. However, the control architectureof the utility-side control system 720 may be distributed in anyappropriate fashion, including where utility-side control units of theutility-side control system 720 are able to communicate with at leastone other utility-side control unit of the utility-side control system720.

One embodiment of a GIC monitoring protocol is presented in FIG. 20, isidentified by reference numeral 750, and will be discussed in relationto the power transmission system 700 of FIG. 19. The GIC monitoringprotocol 750 includes monitoring at least one power line 16, and in atleast one zone 710 of the power transmission system 700, for theexistence of a geomagnetically-induced current or a GIC 740 (step 752).Step 752 of the GIC monitoring protocol 750 may be executed in anyappropriate manner, including through a GIC device 730 that is installedon a power line 16 of the power transmission system 700. As noted abovein the discussion of the power transmission system 700, one or more GICdevices 730 may be installed on at least one power line 16 within one ormore zones 710 of the power transmission system 700, including havingmultiple GIC devices 730 installed on each power line 16 within eachzone 710 of the power transmission system 700 (e.g., including wheremultiple GIC devices 730 are spaced along a given power line 16 within agiven zone 710).

The power line(s) 16 within one or more zones 710 of the powertransmission system 700 may be monitored on at least some basis (e.g.,continually) pursuant to step 752 of the GIC monitoring protocol 750. Inthe event that a GIC 740 is identified on a given power line 16 within agiven zone 710 (step 754), a GIC communication may be sent (directly orindirectly) to the utility-side control system 720 regarding such a GIC740 (step 756). A given GIC device 730 of the power transmission system700 may be used to execute each of steps 754 and 756 of the GICmonitoring protocol 750. In any case, a communication pursuant to step756 could embody information such as the magnitude of the identified GIC740, a time at which the GIC 740 was identified (e.g., a time stamp),the power line 16 on which the GIC 740 exists, at least the generallocation of the GIC 740, and the like.

A communication pursuant to step 756 of the GIC monitoring protocol 750may be utilized in any appropriate manner and for any appropriatepurpose(s) by the utility-side control system 720 of the powertransmission system 700. For instance, the utility-side control system720 could use information on a GIC 740 identified by the GIC monitoringprotocol 750 to initiate one or more actions. Consider the case where aGIC 740 is identified in a given zone 710 of the power transmissionsystem 700 through the GIC monitoring protocol 750. A communicationpursuant to step 756 of the protocol 750 could be used to predict whenthe identified GIC 740 may arrive at one or more other zones 710 of thepower transmission system 700 (e.g., based upon the movement of the Sunrelative to the Earth). Steps could be taken by or through theutility-side control system 720 to protect one or more electricalcomponents that may be part of or otherwise linked to the powertransmission system 700 within one or more zones 710 that may at somelater point-in-time be exposed to the GIC 740 (or a similar current)that was identified pursuant to the GIC monitoring protocol 750.

Based upon the foregoing, it should be appreciated that the GICmonitoring protocol 750 of FIG. 20 could be implemented by the powertransmission system 400 of FIG. 13A and discussed above. At least oneDSR 30 in one or more DSR arrays 410 of the power transmission system400 could include a GIC monitoring system 600 (thereby encompassinghaving multiple DSRs 30 in a given DSR array 410 each include a GICmonitoring system 600, having at least one DSR 30 in each DSR array 410of the power transmission system 400 include a GIC monitoring system600, or both). Each DSR 30 in one or more DSR arrays 410 of the powertransmission system 400 could include a GIC monitoring system 600,including where each DSR 30 in each DSR array 410 of the powertransmission system 400 includes a GIC monitoring system 600. In anycase, communications pursuant to step 756 of the GIC monitoring protocol750 of FIG. 20 could utilize the communication architecture discussedabove in relation to the power transmission system 400 (e.g., havingDSRs 30 within a given DSR array 410 communicate directly with theircorresponding DSR array controller(s) 410, which in turn may communicate(directly or indirectly) with the utility-side control system 430; usingDSRs 30 of a given DSR array 410 to relay a communication to theircorresponding DSR array controller(s) 410, which in turn may communicate(directly or indirectly) with the utility-side control system 430).

The foregoing description of the present invention has been presentedfor purposes of illustration and description. Furthermore, thedescription is not intended to limit the invention to the form disclosedherein. Consequently, variations and modifications commensurate with theabove teachings, and skill and knowledge of the relevant art, are withinthe scope of the present invention. For instance, unless otherwise notedherein to the contrary, other shapes or geometries may be appropriatefor various components of the illustrated embodiments. The embodimentsdescribed hereinabove are further intended to explain best modes knownof practicing the invention and to enable others skilled in the art toutilize the invention in such, or other embodiments and with variousmodifications required by the particular application(s) or use(s) of thepresent invention. It is intended that the appended claims be construedto include alternative embodiments to the extent permitted by the priorart.

1. A device for monitoring geomagnetically-induced currents in a powertransmission line, comprising: a magnetic core disposed about at leastpart of a power transmission line, the core being configured to providean air gap therein; a magnetic sensor positioned in the air gap to sensemagnetic fields and produce an output signal representative of themagnetic fields; and a signal processing unit that receives the outputsignal and determines the magnitude of a geomagnetically-induced currentin the power transmission line therefrom.
 2. A device as defined inclaim 1, wherein the device is configured for mounting onto a power lineby at least substantially surrounding the power transmission line.
 3. Adevice as claimed in claim 1, further including an upper housing and alower housing that are configured for placement around a transmissionpower line and for attachment to each other to contain the core, sensor,and signal processing unit therein.
 4. A device as claimed in claim 1,wherein the core includes at least two separate core portions.
 5. Adevice as claimed in claim 1, wherein the core includes at least threeseparate core portions.
 6. A device as claimed in claim 5, wherein oneof the three separate core portions is configured to extendapproximately 180 degrees around the power transmission line.
 7. Adevice as claimed in claim 5, wherein two of the three separate coreportions are each configured to extend approximately 90 degrees aroundthe power transmission line.
 8. A device as claimed in claim 1, whereinthe signal processing unit processes signals at or near DC with a DCprocessing portion.
 9. A device as claimed in claim 8, wherein the DCprocessing portion includes a low pass filter.
 10. A device as claimedin claim 8, wherein the DC processing portion includes a unit fordetermining the mean of the signals and providing a DC component signalrepresentative thereof.
 11. A device as claimed in claim 1, wherein thesignal processing unit separately processes AC signals and signals at ornear DC with an AC processing portion and a DC processing portion,respectively.
 12. A device as claimed in claim 11, wherein the ACprocessing portion includes a unit for determining the RMS value of thesignal and providing an AC component signal representative thereof. 13.A device as claimed in claim 11, wherein the AC processing portionincludes a high pass filter.
 14. A device as claimed in claim 13,wherein the AC processing portion includes a unit for determining theRMS value of the signal and providing an AC component signalrepresentative thereof.
 15. A device as claimed in claim 14, wherein theAC processing portion includes a ratio-determining unit that determinesthe ratio of a reference signal to the AC component signal and producesa ratio signal representative thereof.
 16. A device as claimed in claim15, wherein the reference signal is determined externally by a differentAC current monitor.
 17. A device as claimed in claim 1, wherein thesignal processing unit separately processes AC signals and signals at ornear DC with an AC processing portion and a DC processing portion,respectively; wherein the DC processing portion includes a unit fordetermining the mean of the signals and providing a DC component signalrepresentative thereof; wherein the AC processing portion includes aunit for determining the RMS value of the signal and providing an ACcomponent signal representative thereof; wherein the AC processingportion includes a ratio-determining unit that determines the ratio of areference signal to the AC component signal and produces a ratio signalrepresentative thereof; and wherein the signal processing unit includesa multiplier unit that multiplies the DC component signal by the ratiosignal.
 18. A device as claimed in claim 1, wherein the signalprocessing unit determines a DC component and an AC component; andwherein the AC component is compared to a reference signalrepresentative of an external measurement of the AC current in the powerline and, based on the comparison, the DC component is adjusted inproportion thereto.
 19. A device as defined in claim 1, wherein thedevice includes a transmitter and an antenna for communicatinggeomagnetically-induced current information to an external device.
 20. Adevice as defined in claim 19, wherein the external device includes areceiver for receiving information related to geomagnetically-inducedcurrents.
 21. A device as defined in claim 1, wherein the deviceincludes a current transformer for drawing current off of the powertransmission line to provide operating power to the device.
 22. A deviceas defined in claim 1, wherein the magnetic sensor includes a Halleffect sensor.
 23. A device as defined in claim 22, wherein the outputsignal from the sensor is an analog signal and the device includes ananalog-to-digital (A/D) converter.
 24. A device as defined in claim 23,wherein the analog signal is provided from the sensor to the A/Dconverter via a twisted pair of wires.
 25. A device as defined in claim1, wherein the device includes an injecting unit for injecting reactanceinto the power transmission line.
 26. A device as defined in claim 25,wherein the injecting unit includes a coil placed relative to a powertransmission line in order to inject the reactance therein.
 27. A methodof operating a power transmission system, comprising: monitoring acurrent on a power transmission line using a geomagnetically-inducedcurrent (GIC) device that is installed on said power transmission line;identifying an existence and magnitude of a geomagnetically-inducedcurrent on said power transmission line from said monitored current,wherein said identifying step is executed by said GIC device; andsending a communication from said GIC device to a first component ofsaid power transmission system and in response to said identifying step.28. A device as claimed in claim 1, wherein the magnetic sensor is notconnected to ground.
 29. A device as claimed in claim 1, wherein themagnetic sensor is isolated from ground.